doc/go1.2: document that godoc and vet will always be installed to their old...

doc/go1.2: document that godoc and vet will always be installed to their old locations (not $GOPATH/bin).

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/13830043

doc/go1.2.html

@@ -175,6 +175,8 @@ include these binaries, so users of these distributions are unaffected.
 
 <p>
 When building from source, users must use "go get" to install godoc and vet.
+(The binaries will continue to be installed in their usual locations, not
+<code>$GOPATH/bin</code>.)
 </p>
 
 <pre>