Bail out vmtoolsd early when there are RPC errors.

Bail out vmtoolsd early when there are RPC errors.

VMX state machine could give up quiescing operation for various
reasons when vmtoolsd is busy performing necessary state transitions.
Once VMX gives up quiescing operation, there is no point in
vmtoolsd continuing with it. vmtoolsd should also give up the
operation asap. vmtoolsd can detect VMX state machine change
when it gets errors sending VMBACKUP_PROTOCOL_EVENT_SET RPC.

RPC errors are only used as a trigger to abort the operation.
We ignore the RPC errors that might occur after aborting the
operation.