misc/vim: Define import commands on buffer switch
misc/vim: Define import commands on buffer switch

This change fixes the import plugin so that the
defined commands are available when opening a new
Go buffer from within Vim itself.

R=adg, rsc
CC=golang-dev
http://codereview.appspot.com/3998053

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

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