Fix leak of parser state in virJSONValueFromString

If OOM or another error occurs in virJSONValueFromString the
parser state object will be leaked.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/util/virjson.c

@@ -1014,6 +1014,7 @@ cleanup:
         for (i = 0; i < parser.nstate; i++) {
             VIR_FREE(parser.state[i].key);
         }
+        VIR_FREE(parser.state);
     }
 
     VIR_DEBUG("result=%p", parser.head);