Fix: disarming spear trap chances luck check was inverted.

From Hack'EM git commit 7dff9ee.

Author: k21971

doc/evilhack-changelog.md

@@ -3361,4 +3361,5 @@ The following changes to date are:
 - Fix: if the player blows up their bag of holding, make known the bag,
   and the object placed inside of it that made the bag blow up
 - Fix: Tiamat couldn't fly
+- Fix: disarming spear trap chances luck check was inverted
 

src/trap.c

@@ -4987,7 +4987,10 @@ struct trap *ttmp;
         return fails;
     You("disarm %s spear trap.", the_your[ttmp->madeby_u]);
 
-    if (rnl(10) > 5) {
+    /* Luck:   0       +2      +5      +8      +11
+     * Chance: 14.3%   28.2%   42.1%   56.1%   70.0%
+     */
+    if (rnl(7) == 0) {
         switch (rn2(5)) {
         case 0:
             cnv_trap_obj(SPEAR, 1, ttmp, FALSE);