fetch: do not create ref from empty name
fetch: do not create ref from empty name

Previously, the refspec "<src>:" would be expanded to
"<src>:refs/heads/". Instead, treat an empty <dst> just like refspecs
without a colon.

Signed-off-by: Clemens Buchacher <3561697699be488d2983f82b126a1881ffc3afbc@aon.at>
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