ndb/include/mgmapi/mgmapi.h:
  add one function
ndb/src/mgmapi/mgmapi.cpp:
  add one function to get cluster loglevel
ndb/src/mgmsrv/Services.cpp:
  addn one function to deal with get log level
ndb/src/mgmsrv/Services.hpp:
  add getClusterLogLevel() function define