Ruleset: Let Spy units to do untargeted tech theft and city sabotage again.

Freeciv-web don't yet support targeted tech theft and targeted sabotage.
Spies were therefore allowed to do the untargeted version of these actions
in git commit 1ece17d8e5128ac94a1dd61d26ecc02e41e09aae. This permission were
removed in git commit 8d1956cf991b09ebbe4a783f169cb38da40c35bf during an
update of the Freeciv version. Bring it back.