Don't use -C in "git diff"

Right now it confuses at least git-diff-files, since it leaves
all the files (whether changed or not) in the diff queue.

git-diff-script

@@ -3,13 +3,13 @@ rev=($(git-rev-parse --revs-only "$@"))
 flags=($(git-rev-parse --no-revs "$@"))
 case "${#rev[*]}" in
 0)
-	git-diff-files -p -C "$@";;
+	git-diff-files -p "$@";;
 1)
-	git-diff-cache -p -C "$@";;
+	git-diff-cache -p "$@";;
 2)
 	begin=$(echo "${rev[1]}" | tr -d '^')
 	end="${rev[0]}"
-	git-diff-tree -p -C $flags $begin $end;;
+	git-diff-tree -p $flags $begin $end;;
 *)
 	echo "I don't understand"
 	exit 1;;