Scripts/Commands: Fix memory leak in ".reload command"

Free commandTableCache object before assigning it the result of malloc()

(cherry picked from commit c6c09423fd)

src/server/game/Chat/Chat.cpp

@@ -81,6 +81,7 @@ ChatCommand* ChatHandler::getCommandTable()
 
             // cache top-level commands
             size_t added = 0;
+            free(commandTableCache);
             commandTableCache = (ChatCommand*)malloc(sizeof(ChatCommand) * total);
             ASSERT(commandTableCache);
             memset(commandTableCache, 0, sizeof(ChatCommand) * total);