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)