Fixes based on review by Tomas


ndb/src/mgmapi/mgmapi.cpp:
  Return immediately if ndb_mgm_get_version fails.
  correctly use new protocol for versions > 5.1
ndb/src/mgmsrv/Services.cpp:
  Only have 1 version of 'stop all' with reply being dependent on if the optional
  stop parameter is supplied.
ndb/src/mgmsrv/Services.hpp:
  Only 1 version of stopAll