[OWL-1103][nqm-agent] Eliminate global variable
[OWL-1103][nqm-agent] Eliminate global variable

`rpcTimeout` has been removed.

Cepave/open-falcon-backend,Cepave/open-falcon-backend,masato25/open-falcon-backend,masato25/open-falcon-backend,masato25/open-falcon-backend,masato25/open-falcon-backend,Cepave/open-falcon-backend,masato25/open-falcon-backend,masato25/open-falcon-backend,Cepave/open-falcon-backend,Cepave/open-falcon-backend,Cepave/open-falcon-backend