Closes #6997 - Allows upsd to runas a non-privileged user.
If any driver is running as non-privileged user, the last driver's
user will be used as the server non-privileged user, otherwise the
user specified in config upsd, otherwise nut. Previously the
localisation of RUNAS variable was in the wrong locations.

Signed-off-by: Daniel F. Dickinson <cshored@thecshore.com>