subtree: use named variables instead of "$@" in cmd_pull

'cmd_pull' already checks that only two arguments are given,
'repository' and 'ref'. Define variables with these names instead of
using the positional parameter $2 and "$@".

This will allow a subsequent commit to pass 'repository' to 'cmd_merge'.

Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/subtree/git-subtree.sh

@@ -1005,9 +1005,11 @@ cmd_pull () {
 	then
 		die "fatal: you must provide <repository> <ref>"
 	fi
+	repository="$1"
+	ref="$2"
 	ensure_clean
-	ensure_valid_ref_format "$2"
-	git fetch "$@" || exit $?
+	ensure_valid_ref_format "$ref"
+	git fetch "$repository" "$ref" || exit $?
 	cmd_merge FETCH_HEAD
 }