common-main: call git_setup_gettext()

This should be part of every program, as otherwise users do
not get translated error messages. However, some external
commands forgot to do so (e.g., git-credential-store). This
fixes them, and eliminates the repeated code in programs
that did remember to use it.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

common-main.c

@@ -37,6 +37,8 @@ int main(int argc, char **av)
 	 */
 	sanitize_stdfds();
 
+	git_setup_gettext();
+
 	argv[0] = git_extract_argv0_path(argv[0]);
 
 	restore_sigpipe_to_default();