Quick Polymorph patch.

[Mark Wedel <master@rahul.net>]

 Apply this to the common/treasure.c file.  It should prevent the core
dumps that polymorph causes:

*** 667,672 ****
--- 653,659 ----
  void fix_generated_item(object *op,int difficulty, int max_magic) {
    int was_magic = op->magic;
  
+   if (difficulty<1) difficulty=1;
    if (op->arch == crown_arch) {
      set_magic(difficulty>25?30:difficulty+5, op, max_magic);
      generate_artifact(op,difficulty);
***************

   Mark Wedel
master@rahul.net