Documentation: fix documentation AsciiDoc links for external urls

Turns out that putting 'link:' before the 'http' is actually superfluous
in AsciiDoc, as there's already a predefined macro to handle it.

"http, https, [etc] URLs are rendered using predefined inline macros."
http://www.methods.co.nz/asciidoc/userguide.html#_urls

"Hypertext links to files on the local file system are specified
using the link inline macro."
http://www.methods.co.nz/asciidoc/userguide.html#_linking_to_local_documents

Despite being superfluous, the reference implementation of AsciiDoc
tolerates the extra 'link:' and silently removes it, giving a functioning
link in the generated HTML. However, AsciiDoctor (the Ruby implementation
of AsciiDoc used to render the http://git-scm.com/ site) does /not/ have
this behaviour, and so generates broken links, as can be seen here:

http://git-scm.com/docs/git-cvsimport (links to cvs2git & parsecvs)
http://git-scm.com/docs/git-filter-branch (link to The BFG)

It's worth noting that after this change, the html generated by 'make html'
in the git project is identical, and all links still work.

Signed-off-by: Roberto Tyley <roberto.tyley@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-cvsimport.txt

@@ -21,8 +21,8 @@ DESCRIPTION
 *WARNING:* `git cvsimport` uses cvsps version 2, which is considered
 deprecated; it does not work with cvsps version 3 and later.  If you are
 performing a one-shot import of a CVS repository consider using
-link:http://cvs2svn.tigris.org/cvs2git.html[cvs2git] or
+http://cvs2svn.tigris.org/cvs2git.html[cvs2git] or
-link:https://github.com/BartMassey/parsecvs[parsecvs].
+https://github.com/BartMassey/parsecvs[parsecvs].
 
 Imports a CVS repository into Git. It will either create a new
 repository, or incrementally import into an existing one.

Documentation/git-filter-branch.txt

@@ -436,7 +436,7 @@ git-filter-branch allows you to make complex shell-scripted rewrites
 of your Git history, but you probably don't need this flexibility if
 you're simply _removing unwanted data_ like large files or passwords.
 For those operations you may want to consider
-link:http://rtyley.github.io/bfg-repo-cleaner/[The BFG Repo-Cleaner],
+http://rtyley.github.io/bfg-repo-cleaner/[The BFG Repo-Cleaner],
 a JVM-based alternative to git-filter-branch, typically at least
 10-50x faster for those use-cases, and with quite different
 characteristics:
@@ -455,7 +455,7 @@ characteristics:
   _is_ possible to write filters that include their own parallellism,
   in the scripts executed against each commit.
 
-* The link:http://rtyley.github.io/bfg-repo-cleaner/#examples[command options]
+* The http://rtyley.github.io/bfg-repo-cleaner/#examples[command options]
   are much more restrictive than git-filter branch, and dedicated just
   to the tasks of removing unwanted data- e.g:
   `--strip-blobs-bigger-than 1M`.

Documentation/gitcore-tutorial.txt

@@ -1443,7 +1443,7 @@ Although Git is a truly distributed system, it is often
 convenient to organize your project with an informal hierarchy
 of developers. Linux kernel development is run this way. There
 is a nice illustration (page 17, "Merges to Mainline") in
-link:http://www.xenotime.net/linux/mentor/linux-mentoring-2006.pdf[Randy Dunlap's presentation].
+http://www.xenotime.net/linux/mentor/linux-mentoring-2006.pdf[Randy Dunlap's presentation].
 
 It should be stressed that this hierarchy is purely *informal*.
 There is nothing fundamental in Git that enforces the "chain of

Documentation/gitcvs-migration.txt

@@ -117,7 +117,7 @@ Importing a CVS archive
 -----------------------
 
 First, install version 2.1 or higher of cvsps from
-link:http://www.cobite.com/cvsps/[http://www.cobite.com/cvsps/] and make
+http://www.cobite.com/cvsps/[http://www.cobite.com/cvsps/] and make
 sure it is in your path.  Then cd to a checked out CVS working directory
 of the project you are interested in and run linkgit:git-cvsimport[1]:
 

Documentation/gitweb.txt

@@ -84,7 +84,7 @@ separator (rules for Perl's "`split(" ", $line)`").
 
 * Fields use modified URI encoding, defined in RFC 3986, section 2.1
 (Percent-Encoding), or rather "Query string encoding" (see
-link:http://en.wikipedia.org/wiki/Query_string#URL_encoding[]), the difference
+http://en.wikipedia.org/wiki/Query_string#URL_encoding[]), the difference
 being that SP (" ") can be encoded as "{plus}" (and therefore "{plus}" has to be
 also percent-encoded).
 +

Documentation/technical/http-protocol.txt

@@ -500,7 +500,7 @@ TODO: Document this further.
 References
 ----------
 
-link:http://www.ietf.org/rfc/rfc1738.txt[RFC 1738: Uniform Resource Locators (URL)]
+http://www.ietf.org/rfc/rfc1738.txt[RFC 1738: Uniform Resource Locators (URL)]
-link:http://www.ietf.org/rfc/rfc2616.txt[RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1]
+http://www.ietf.org/rfc/rfc2616.txt[RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1]
 link:technical/pack-protocol.html
 link:technical/protocol-capabilities.html