The right places to manually put systemd user units is:
* /etc/systemd/user if you want them to be available to all users,
* ${XDG_CONFIG_HOME}/systemd/user for a single user.
The upstream rationale is: user configuration goes to /etc/systemd or
$XDG_CONFIG_HOME/systemd, while package provided config goes to
/usr/lib/systemd or $XDG_DATA_HOME/systemd.
If offlineimap ever installs systemd units from the install scripts, it
should install them to /usr/lib/systemd/user.
Signed-off-by: Abdo Roig-Maranges <abdo.roig@gmail.com>
