* src/esx/esx_vi.[ch]: convert esxVI_RemoteRequest_Execute() to a
  simpler esxVI_Context_Execute() version, remove esxVI_RemoteRequest
  and convert esxVI_RemoteResponse to esxVI_Response
* src/esx/esx_vi_methods.c: update and simplify callers to use
  esxVI_Context_Execute() instead of esxVI_RemoteRequest_Execute()