Housekeeping: Cleaning up the clean-up process.

src/clean.bash:
        Add clean-ups for previously overlooked directories.
doc/codelab/wiki/Makefile:
        Dropped "index.html" from CLEANFILES so it will not be
        deleted on cleaning.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5476050

doc/codelab/wiki/Makefile

@@ -8,7 +8,7 @@ all: index.html
 
 include ../../../src/Make.common
 
-CLEANFILES+=index.html srcextract.bin htmlify.bin get.bin
+CLEANFILES+=srcextract.bin htmlify.bin get.bin
 
 index.html: wiki.html srcextract.bin htmlify.bin
 	PATH=.:$$PATH awk '/^!/{system(substr($$0,2)); next} {print}' < wiki.html | tr -d '\r' > index.html

src/clean.bash

@@ -22,6 +22,8 @@ rm -f "$GOROOT"/lib/*.a
 for i in lib9 libbio libmach cmd pkg \
 	../misc/cgo/gmp ../misc/cgo/stdio \
 	../misc/cgo/life ../misc/cgo/test \
+	../misc/dashboard/builder ../misc/goplay\
+	../doc/codelab/wiki\
 	../test/bench ../test/garbage
 do
 	# Do not use gomake here. It may not be available.