test: test issue 7884 (already fixed)
test: test issue 7884 (already fixed)

I don't know when the bug was fixed, but empirically it was.
Make sure it stays fixed by adding a test.

Fixes issue 7884.

LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://codereview.appspot.com/93500043

tv42/old-go,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go,pombredanne/go-deleteme,tv42/old-go,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go,tv42/old-go,tv42/old-go,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go