Remove unused and obsolete mgmapi functionality (that did nothing anyway).


storage/ndb/include/mgmapi/mgmapi.h:
  remove dead internal ndb_mgm_get_stat_port function.
storage/ndb/src/mgmapi/mgmapi.cpp:
  remove ndb_mgm_get_stat_port
  
  was only marked for internal use.
  dead (in 5.0 as well, only removed in 5.1 for safety)
storage/ndb/src/mgmsrv/Services.cpp:
  remove dead 'get statport'
storage/ndb/src/mgmsrv/Services.hpp:
  remove dead getStatPort