push: rename config variable for more general use

The 'pushNonFastForward' advice config can be used to squelch several
instances of push-related advice.  Rename it to 'pushUpdateRejected' to
cover other reject scenarios that are unrelated to fast-forwarding.
Retain the old name for compatibility.

Signed-off-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/push.c b/builtin/push.c
index 83a3cc8..cf5ecfa 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -226,21 +226,21 @@
 
 static void advise_pull_before_push(void)
 {
-	if (!advice_push_non_ff_current || !advice_push_nonfastforward)
+	if (!advice_push_non_ff_current || !advice_push_update_rejected)
 		return;
 	advise(_(message_advice_pull_before_push));
 }
 
 static void advise_use_upstream(void)
 {
-	if (!advice_push_non_ff_default || !advice_push_nonfastforward)
+	if (!advice_push_non_ff_default || !advice_push_update_rejected)
 		return;
 	advise(_(message_advice_use_upstream));
 }
 
 static void advise_checkout_pull_push(void)
 {
-	if (!advice_push_non_ff_matching || !advice_push_nonfastforward)
+	if (!advice_push_non_ff_matching || !advice_push_update_rejected)
 		return;
 	advise(_(message_advice_checkout_pull_push));
 }