Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.
Sponsored by: Netflix
There are some _write callbacks left only returning EROFS, replace them
by null_write. return EROFS from null_write().
Reviewed by: cem, imp, kan
Differential Revision: https://reviews.freebsd.org/D14523