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.
doh, excellent point, added a regex that works in our test environment and in the environment we discovered the vulnerability in (simply looks for parts of a Cisco IOS banner string)