Fixups to the Linksys module

Professionalizes the description a little, but more importantly, handles
LANIP better, I think. Instead of faking a 1.1.1.1 address, just detect
if it's set or not in a method and return the right thing accordingly.

Please test this before landing, obviously. I think it's what's
intended.
Merge branch 'bugs/linksys-fixes' of github.com:todb-r7/metasploit-framework into todb-r7-bugs/linksys-fixes