test: testConnectClose: Set privateData to NULL in all cases

Set privateData to NULL also for a connection that uses @defaultConn
as privateData regardless of whether @defaultConn was freed or
not. @defaultConn is shared between multiple connections and it's
ensured that there will be no memory leak by counting references.

Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>

src/test/test_driver.c

@@ -1472,6 +1472,7 @@ static int testConnectClose(virConnectPtr conn)
         dflt = true;
         virMutexLock(&defaultLock);
         if (--defaultConnections) {
+            conn->privateData = NULL;
             virMutexUnlock(&defaultLock);
             return 0;
         }