conflicting countdowns again

Use the make_foo() intrinsic set/reset routines instead of trying
to manipulate the intrinsics directly.  Previous patch left Dex
down by 1 if stoning caused wounded legs to be fixed, and left
delayed killer allocated if stoning cured sliming or vice versa.

src/pray.c

@@ -524,7 +524,7 @@ int trouble;
         break;
     }
     case TROUBLE_WOUNDED_LEGS:
-        heal_legs();
+        heal_legs(0);
         break;
     case TROUBLE_STUNNED:
         make_stunned(0L, TRUE);