added make of mgmapi_logevent_example


ndb/examples/Makefile:
  added make of mgmapi_logevent_example
ndb/examples/ndbapi_async_example/ndbapi_async.cpp:
  use select for sleep instead of nanosleep for portability reasons
ndb/examples/ndbapi_scan_example/ndbapi_scan.cpp:
  use select for sleep instead of nanosleep for portability reasons