Add the MTA users 'mailnull' and 'smmp'.
Add the MTA users 'mailnull' and 'smmp'.

PR:		conf/34535
Submitted by:	Ceri <setantae@submonkey.net>
MFC after:	1 week

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase