Don't advice a player to declare war on himself.

Don't advice a player to declare war on himself.

The player can ask what actions a unit can perform to targets located at a
specific tile in two ways. He can ask directly via the unit_get_actions
packet. Ordering the unit to move to the tile is sometimes interpreted as an
indirect question. When no action is possible the server will notify the
player. If able to it will try to explain why no action was possible.

An action may be impossible because the actor isn't at war with the target.
The server will consider this when trying to find an explanation why no
action could be performed. If declaring war may make an action legal it will
let the player know.

A player can't declare war on himself or on a team mate. Informing the
player that a war may make some action legal is therefore pointless.

See gna bug #25551

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@35076 a0f10bec-cc02-0410-94fc-a9cfff90b4cd