Audit rev-parse users again.

Some callers to rev-parse were using the output selection flags
inconsistently.

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

git-branch-script

@@ -25,7 +25,7 @@ case "$#" in
 	head="$2^0" ;;
 esac
 branchname="$1"
-rev=$(git-rev-parse --revs-only --verify "$head") || exit
+rev=$(git-rev-parse --verify "$head") || exit
 
 [ -e "$GIT_DIR/refs/heads/$branchname" ] && die "$branchname already exists"