virtiofsd: passthrough_ll: set FUSE_LOG_INFO as default log_level

Just noticed that although help message says default log level is INFO,
it is actually 0 (EMRGE) and no mesage will be shown when error occurs.
It's better to follow help message.

Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Message-Id: <20201008110148.2757734-1-misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

tools/virtiofsd/passthrough_ll.c

@@ -2878,12 +2878,11 @@ int main(int argc, char *argv[])
         goto err_out1;
     }
 
-    /*
-     * log_level is 0 if not configured via cmd options (0 is LOG_EMERG,
-     * and we don't use this log level).
-     */
     if (opts.log_level != 0) {
         current_log_level = opts.log_level;
+    } else {
+        /* default log level is INFO */
+        current_log_level = FUSE_LOG_INFO;
     }
     lo.debug = opts.debug;
     if (lo.debug) {