git push: remove incomplete options list from help text

'git push -h' shows usage text with incomplete list of options and then
has a separate list of options that are supported. Imitate the way other
commands (I looked at 'git diff' for an example) show their options.

Signed-off-by: しらいし ななこ <nanako3@lavabit.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-push.c

@@ -10,7 +10,7 @@
 #include "parse-options.h"
 
 static const char * const push_usage[] = {
-	"git push [--all | --mirror] [-n | --dry-run] [--porcelain] [--tags] [--receive-pack=<git-receive-pack>] [--repo=<repository>] [-f | --force] [-v] [<repository> <refspec>...]",
+	"git push [<options>] [<repository> <refspec>...]",
 	NULL,
 };