Bump version so upgrades work

See merge request devuan-packages/slim!5

/etc/X11/Xsession is an executable script.

The Debian NMU 1.3.6-5.1 is noop for Devuan as it contained only slim.service
fixes. However this version is in beowulf.

Devuan ascii has 1.3.6-5.1+devuan2 and ceres slim-1.3.6-5+devuan5

This version bump allows all these to be upgraded.

Merge LeePen/slim:wip/devuan

See merge request devuan-packages/slim!4

This is to work around a bug caused by changes to the default
compression level used in the unstable & beowulf suites changing from 9
to 6

* add missing line continuation

* themes to be provided by desktop-base packages
  and others using the dpkg alternatives system

* set slim to use slim-desktop-theme (alternatives system)
* refresh quilt patches to get rid of warnings

Add devuan-curve theme to SLiM

This adds a _leafy_ green theme for Devuan.

Is there a need to update `slim.conf` to set `current_theme` to that theme instead of the default?

See merge request !1

- ensure we are starting slim under systemd only when selected as
 default. (Closes: #748668)