fix issue https://savannah.cern.ch/bugs/?67532: do not throw exception in case of USER command failures; this result ers::fatal error generated by Run Control framework and moves application to ERROR state, that cannot be recovered by present Run Control; instead of exception throw, the ers::error should be reported do not print consistency warnings each time, when a status of resource is changed; instead, the warnings have to be reported only when ResInfoProvider is configured check parameters of USER command and report non-existent resources as errors (by mistake at present such fake resources are silently ignored)