completion: get rid of empty COMPREPLY assignments
completion: get rid of empty COMPREPLY assignments

There's no functional reason for those, the only purpose they are
supposed to serve is to say "we don't provide any words here", but
even for that it's not used consistently.

Signed-off-by: Felipe Contreras <de77a8b9cd239b204c19c52ed62e48ab47243362@gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git