debian: add 'dbus' as build dep

2f4e37f4 is not enough, we also need
'dbus' when building the package as the tests as also run at this point.

Signed-off-by: Guillaume Desmottes <guillaume.desmottes@collabora.co.uk>
Reviewed-by: Héctor Orón Martínez <hector.oron@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D4304

debian/control

@@ -17,6 +17,7 @@ Build-Depends:
  libgirepository1.0-dev,
  libglib2.0-dev,
  libsystemd-dev,
+ dbus
 Standards-Version: 3.9.6
 
 Package: libtraprain-common-0-0