Findbugs finding fixed

1. Findbugs finding fixed - a dead store caused by https://github.com/hazelcast/hazelcast/commit/e1b216eb769f6f011d2a2eae6521e4e8587ffb02#diff-d41d8cd98f00b204e9800998ecf8427e
2. CallId is no longer leaking from the registerInvocation()