[freeciv-ai] improve diplomat logging + bugfix

["Per I. Mathisen" <per@xxxxxxxxxxx>]

This patch improves logging in ai/aidiplomat.c, and also solves a little
bug:

-    time_to_dest /= ut->move_rate;
     time_to_dest *= (time_to_dest/2); /* No long treks, please */

     /* Almost kill_desire */
     want = (p_success * gain - p_failure * loss) / 100
-           - SHIELD_WEIGHTING * time_to_dest;
+           - SHIELD_WEIGHTING * (time_to_dest / ut->move_rate);

If time_to_dest is == ut->move_rate, the penalty for long treks is never
applied, leading to ballooning want in this case.

Since I can't see that there can be any controversial stuff in here, I'm
committing this at once.

  - Per

diplog1.diff
Description: Text document