Comment 6 for bug 1475850

A reinstall example:

Preparing to unpack .../acpid_1%3a2.0.23-1ubuntu1_i386.deb ...
Unpacking acpid (1:2.0.23-1ubuntu1) over (1:2.0.23-1ubuntu1) ...
Processing triggers for man-db (2.7.3-1) ...
Processing triggers for systemd (225-1ubuntu4) ...
Processing triggers for ureadahead (0.100.0-19) ...
ureadahead will be reprofiled on next reboot
Setting up acpid (1:2.0.23-1ubuntu1) ...

so i'm not seeing your error here (GS session Wily i386)