Rule set sanity check: the unit type flag "Spy" requires that "Diplomat" is set

Requested by Marko Lindqvist <cazfi>

See patch #4682

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24845 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Renamed variable PO_DOMAINS as PODOMAINS.

See patch #4674


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24847 a0f10bec-cc02-0410-94fc-a9cfff90b4cd