[Freeciv-Dev] (PR#7305) caravan with 0 moves left can still do stuff

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=7305 >

A caravan with 0 moves left won't be activated by the client.  But if
this caravan is in a city, it can still do some actions:
help-build-wonder, establish-traderoute, etc.

It should be easy enough to check for this special case.  A new helper
function can_unit_do_anything_else_this_turn() may be helpful.  Of
course, if the player hits the space-bar (end turn) for the caravan it
should not be re-activated.

Reported by Michael Mielke (mlm) on #freeciv.

jason