Add facility to report back to ndb_mgmd what port was used for a connection.

We do not actually do the reporting back yet.


ndb/include/mgmapi/mgmapi_debug.h:
  Add prototype for ndb_mgm_set_connection_int_parameter
ndb/src/mgmapi/mgmapi.cpp:
  Add ndb_mgm_set_connection_int_parameter.
  
  Do 'set connection parameter' ndb_mgm_call
ndb/src/mgmsrv/MgmtSrvr.cpp:
  Add MgmtSrvr::setConnectionDbParameter.
  
  Find the connection between node1 and node2,
ndb/src/mgmsrv/MgmtSrvr.hpp:
  Add prototype for setConnectionDbParameter
ndb/src/mgmsrv/Services.cpp:
  Add 'set connection parameter' cmd and MgmApiSession::setConnectionParameter handler.
ndb/src/mgmsrv/Services.hpp:
  add setConnectionParameter prototype.