Merge branch 'gb/maint-am-patch-format-error-message' into maint

* gb/maint-am-patch-format-error-message:
  am: format is in $patch_format, not parse_patch

Author: gitster

git-am.sh

@@ -305,7 +305,8 @@ split_patches () {
 		msgnum=
 		;;
 	*)
-		if test -n "$parse_patch" ; then
+		if test -n "$patch_format"
+		then
 			clean_abort "Patch format $patch_format is not supported."
 		else
 			clean_abort "Patch format detection failed."