KTR: log IPv4 addresses in hex rather than dotted-quad

When I made the changes in r313821, I fell victim to one of the
classic blunders, the most famous of which is: never get involved
in a land war in Asia. But only slightly less well known is this:
Keep your brain turned on and engaged when making a tedious, sweeping,
mechanical change. KTR can correctly log the immediate integral values
passed to it, as well as constant strings, but not non-constant strings,
since they might change by the time ktrdump retrieves them.

Reported by: glebius
MFC after: 3 days
Sponsored by: Dell EMC