git.c: simplify stripping extension of a file in handle_builtin()
The handle_builtin() starts from stripping of command extension if
STRIP_EXTENSION is enabled. Actually STRIP_EXTENSION does not used
anywhere else.
This patch introduces strip_extension() helper to strip STRIP_EXTENSION
extension from argv[0] with the strip_suffix() instead of manually
stripping.
Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>