apt.py: remove noisy (and redundant) log messages

There are log entries in __virtual__ which are redundant and end up
being written to the log over and over again if certain python modules
are not present, irrespective of whether or not the features which
require these python modules are being used.

They should never have been in __virtual__ in the first place, since
there are already notifications in the functions which make use of these
modules, when those modules are not present.

This commit removes them, which should get rid of a lot of noise in the
minion log.
Merge pull request #5529 from terminalmage/issue5431

apt.py: remove noisy (and redundant) log messages