Add DLSw leak capture module for CVE-2014-7992

Note: I have a zip file that contains a full setup to test for this vulnerability.  It has 2 Win VMs and a GNS3 configuration with 3 routers to enable testing. I would be happy to share. Otherwise you need to build a working DLSw setup to test.
I think this is too specific.  From what I've been able to find, those last two bytes are specifying the message length, which won't necessarily be 347 (0x015b).