Fixing return value.

sql/item_cmpfunc.cc

@@ -947,7 +947,7 @@ get_datetime_value(THD *thd, Item ***item_arg, Item **cache_arg,
     *is_null= item->null_value;
   }
   if (*is_null)
-    return ~(ulonglong) -1;
+    return ~(ulonglong) 0;
   /*
     Convert strings to the integer DATE/DATETIME representation.
     Even if both dates provided in strings we can't compare them directly as

sql/rpl_utility.cc

@@ -164,7 +164,7 @@ uint32 table_def::calc_field_size(uint col, uchar *master_data) const
     break;
   }
   default:
-    length= ~(uint32) -1;
+    length= ~(uint32) 0;
   }
   return length;
 }