Fix-up previous expr changes.

The regexp on the right hand side of expr : operator somehow was
broken.

	expr 'z+pu:refs/tags/ko-pu' : 'z\+\(.*\)'

does not strip '+'; write 'z+\(.*\)' instead.

We probably should switch to shell based substring post 1.3.0;
that's not bashism but just POSIX anyway.

Signed-off-by: Junio C Hamano <junkio@cox.net>

git-parse-remote.sh

@@ -77,7 +77,7 @@ canon_refs_list_for_fetch () {
 		force=
 		case "$ref" in
 		+*)
-			ref=$(expr "z$ref" : 'z\+\(.*\)')
+			ref=$(expr "z$ref" : 'z+\(.*\)')
 			force=+
 			;;
 		esac