BUG/MINOR: mworker: does not create the "default" resolvers in wait mode

When doing a re-exec, the master was creating a "default" resolvers,
which could result in a warning emitted because the "default" resolvers
of the configuration file is not available anymore.

Skip the creating of the "default" resolvers in wait mode, this is not
useful in the master.

Must be backported as far as 2.6.

src/resolvers.c

@@ -3671,6 +3671,9 @@ int resolvers_create_default()
 {
 	int err_code = 0;
 
+	if (global.mode & MODE_MWORKER_WAIT) /* does not create the section if in wait mode */
+		return 0;
+
 	/* if the section already exists, do nothing */
 	if (find_resolvers_by_id("default"))
 		return 0;