testNetworkUpdate: Unlock network at the end

Silly this bug went unnoticed so long. At the beginning we try to
find the passed network in the list of network objects. If found,
it's locked and real work takes place. Then, in the end, the
network object is never unlocked.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/test/test_driver.c

@@ -3835,6 +3835,8 @@ testNetworkUpdate(virNetworkPtr net,
 
     ret = 0;
  cleanup:
+    if (network)
+        virNetworkObjUnlock(network);
     testDriverUnlock(privconn);
     return ret;
 }