tests: qemumonitorjson: Raise the necessary debug level for QAPI schema checks

The debug output of the schema validator on success is not so
interesting that it should be printed when basic debugging is enabled.

Print it only when test debugging is set to 3 and more.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

tests/qemumonitorjsontest.c

@@ -2838,7 +2838,7 @@ testQAPISchema(const void *opaque)
         ret = 0;
     }
 
-    if (virTestGetDebug() ||
+    if (virTestGetDebug() >= 3 ||
         (ret < 0 && virTestGetVerbose())) {
         char *debugstr = virBufferContentAndReset(&debug);
         fprintf(stderr, "\n%s\n", debugstr);