Enhance crash reporting. Fix

LPBug#819711 : optimizer_switch must be reported on segfault
LPBug#820169:  Full query text must be reported on crash

sql/mysqld.cc

@@ -2754,9 +2754,10 @@ the thread stack. Please read http://dev.mysql.com/doc/mysql/en/linux.html\n\n",
     fprintf(stderr, "\nTrying to get some variables.\n"
                     "Some pointers may be invalid and cause the dump to abort.\n");
     fprintf(stderr, "Query (%p): ", thd->query());
-    my_safe_print_str(thd->query(), min(1024, thd->query_length()));
+    my_safe_print_str(thd->query(), thd->query_length());
     fprintf(stderr, "Connection ID (thread ID): %lu\n", (ulong) thd->thread_id);
     fprintf(stderr, "Status: %s\n", kreason);
+    fprintf(stderr, "Optimizer switch: %s\n", optimizer_switch_str);
     fputc('\n', stderr);
   }
   fprintf(stderr, "\