godoc: enable qualified identifiers ("math.Sin") as query strings again
godoc: enable qualified identifiers ("math.Sin") as query strings again

A query string of the form ident.ident will be used both as a qualified
identifier for identifier search and as a regular expression.
Qualified identifier lookup got broken accidentally when introducing
regexp full text search. Cleaned up surrounding logic a bit.

R=rsc
CC=golang-dev
http://codereview.appspot.com/3984042

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