improve verbose message for package_list_command
Instead of only list arg[0] list while command, eg:
old: Reading package list from /usr/bin/env
new: Reading package list from '/usr/bin/env DEBIAN_FRONTEND=noninteractive LC_ALL=C PATH=/bin:/sbin/:/usr/bin:/usr/sbin /usr/bin/dpkg -l
see discussion in: https://groups.google.com/forum/#!topic/help-cfengine/nH6bR-n2x_c
(cherry picked from commit 1d0a8c19c4ea6af44ed990cb99d762f2a1bbcf4f)
also adjust message for old log format
(cherry picked from commit 0ad62f91bfaa0e7fcf45dedf5f1747d576e1713f)
Redmine #6441: Fix software_packages.csv being regenerated every time.

Do not allow '\r' to make it into the package string. If the package
manager puts '\r' at the end of the lines, it will cause later
comparisons to fail, so make sure to filter it out.
(cherry picked from commit 6b3e4608cff3624592ea7e0e901a0f0634f31a2b)