LXQtModule: Set subprocess output to null.
LXQtModule: Set subprocess output to null.

Otherwise QProcess will keep allocating memory to store process output
we never read.

lxde/lxqt-session,lxde/lxqt-session,stefonarch/lxqt-session,stefonarch/lxqt-session,lxde/lxqt-session,stefonarch/lxqt-session