check validity of "configsvr:true" at config validation time

Currently, no check is made at config validation time if the value of "configsvr" in the new replica set config matches the value of the equivalent command line argument "--configsvr". This means if you start nodes without --configsvr and reconfig or initiate with a config that contains "configsvr:true", the reconfig or initiate command succeeds, but all nodes in the replica set immediately transition to REMOVED state.
Instead, the reconfig or initiate command should fail and return an error.