Summary: pcmanfm in Lubuntu used gksu. When we switched to lxqt, it had been deprecated, so we used pkexec. Unfortunately, pkexec just flat out fails. Looking upstream, they use lxqt-sudo, which we have in our install, so going with their default instead.
Test Plan:
1. Open pcmanfm-qt
2. Click on "Tools" in the menu
3. Click on "Open as root"
Should get an lxqt-sudo dialog asking for a password.
Reviewers: tsimonq2
Reviewed By: tsimonq2
Differential Revision: https://phab.lubuntu.me/D7
Simon Quigley
Walter Lapchynski