gobuilder: ignore _test.go files when looking for docs, more logging
gobuilder: ignore _test.go files when looking for docs, more logging

R=n13m3y3r
CC=golang-dev
http://codereview.appspot.com/4918050

pombredanne/go-deleteme,tv42/old-go,dsriram/golang,dsriram/golang,pombredanne/go-deleteme,tv42/old-go,tv42/old-go,gnanderson/go,apparentlymart/golang,dsriram/golang,tv42/old-go,gnanderson/go,apparentlymart/golang,dsriram/golang,tv42/old-go,dsriram/golang,apparentlymart/golang,apparentlymart/golang,dsriram/golang,tv42/old-go,gnanderson/go,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,gnanderson/go,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go,gnanderson/go,pombredanne/go-deleteme,gnanderson/go,gnanderson/go,pombredanne/go-deleteme,dsriram/golang,pombredanne/go-deleteme