bash: remove unnecessary checks for long options with argument

__gitcomp takes care of it since 5447aac7 (bash: fix long option with
argument double completion, 2008-03-05)

Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
Acked-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/completion/git-completion.bash

@@ -643,7 +643,6 @@ _git_branch ()
 	done
 
 	case "${COMP_WORDS[COMP_CWORD]}" in
-	--*=*)	COMPREPLY=() ;;
 	--*)
 		__gitcomp "
 			--color --no-color --verbose --abbrev= --no-abbrev
@@ -1689,7 +1688,6 @@ _git ()
 
 	if [ -z "$command" ]; then
 		case "${COMP_WORDS[COMP_CWORD]}" in
-		--*=*) COMPREPLY=() ;;
 		--*)   __gitcomp "
 			--paginate
 			--no-pager