Reset logging filter function when forking

To ensure child processes will log all error messages, reset
the logging filter function when forking

* src/util/util.c: Reset log filter in fork

src/util/util.c

@@ -384,6 +384,7 @@ int virFork(pid_t *pid) {
            get sent to stderr where they stand a fighting chance
            of being seen / logged */
         virSetErrorFunc(NULL, NULL);
+        virSetErrorLogPriorityFunc(NULL);
 
         /* Make sure any hook logging is sent to stderr, since child
          * process may close the logfile FDs */