the f5 plugin doesn't handle it well if a service is assumed to be registered but actually isn't

[tomdz]

Exception caught in LocalLB::urn:iControl:LocalLB/NodeAddress::set_session_enabled_state()
Exception: Common::OperationFailed
primary_error_code : 16908342 (0x01020036)
secondary_error_code : 0
error_string : 01020036:3: The requested node address (<IP>) was not found.

and

Exception caught in LocalLB::urn:iControl:LocalLB/NodeAddress::get_statistics()
Exception: Common::OperationFailed
primary_error_code : 16908336 (0x01020030)
secondary_error_code : 0
error_string :