BUG/MINOR: server: Fix a wrong error message during 'usesrc' keyword parsing.

'usesrc' setting is not permitted on 'server' lines if not provided after
'source' setting. This is now also the case on 'default-server' lines.
Without this patch parse_server() parser displayed that 'usersrc' is
an unknown keyword.

Should have come with dba9707 commit.
diff --git a/src/server.c b/src/server.c
index b5d8890..40a8d7f 100644
--- a/src/server.c
+++ b/src/server.c
@@ -2207,7 +2207,7 @@
 				}
 				cur_arg += 2;
 			}
-			else if (!defsrv && !strcmp(args[cur_arg], "usesrc")) {  /* address to use outside: needs "source" first */
+			else if (!strcmp(args[cur_arg], "usesrc")) {  /* address to use outside: needs "source" first */
 				Alert("parsing [%s:%d] : '%s' only allowed after a '%s' statement.\n",
 				      file, linenum, "usesrc", "source");
 				err_code |= ERR_ALERT | ERR_FATAL;