Fix: Peaceful demon lords won't follow you across levels

This amends commit b550ba0 so that peaceful demon lords will remain on their level. Before, demon lords would follow you across levels and be angry if they did so---I assumed that peaceful demon lords would only be those who could be bribed, and figured people would mostly only get demon lords following them if they intentionally tried to skip them, so I thought it made sense from a flavor and gameplay standpoint.

However:
1) infidels can get peaceful demon lords as one of their perks, and shouldn't be forced to engage them
2) bribeable demons (read: Asmodeus) don't seem to actually generate as peaceful in their lairs
3) a surprising number of people have triggered the dlord-following behavior without intentionally trying to find an exploit, so angering bribeable demon lords seems a bit vindictive

This commit has no specific provision for bribeable demon lords; if it turns out that Asmodeus is bribeable at some times, this could be revisited. On the other hand, in such a case, skipping the demon lord via bribery is still possible, so perhaps it is unnecessary to prevent skipping them via levelport.

Author: saltwaterterrapin

doc/evilhack-changelog.md

@@ -3349,4 +3349,4 @@ The following changes to date are:
 - New player role: Druid (initial commit)
 - Minor tweaks to Druid role
 - Set default Druid pet name if one isn't set in the player config
-
+- Fix: Peaceful demon lords won't follow you across levels

src/do.c

@@ -1427,7 +1427,9 @@ dlords_stalk()
     for (mtmp = fmon; mtmp; mtmp = mtmp2) {
         /* save in case mtmp gets migrated */
         mtmp2 = mtmp->nmon;
-        if (is_dlord(mtmp->data) || is_dprince(mtmp->data)) {
+        if ((is_dlord(mtmp->data) || is_dprince(mtmp->data))
+            /* infidels can get peaceful dlords who won't hound them */
+            && !mtmp->mpeaceful) {
             migrate_to_level(mtmp, ledger_no(&u.uz), MIGR_STALK, (coord *) 0);
             mtmp->mstate |= MON_MIGRATING;
         }

src/dog.c

@@ -539,7 +539,6 @@ boolean with_you;
             xlocale = u.ux;
             ylocale = u.uy;
             mtmp->mstrategy &= ~STRAT_WAITMASK;
-            mtmp->mpeaceful = 0;
         }
         break;
     case MIGR_PORTAL: