agl-compositor: Remove the step to enable the development repository

As now all the dependecies were moved to target repository there is
no need to enable the development respository, so remove the this
step from the test case.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>

test-cases/agl-compositor.yaml

@@ -21,8 +21,6 @@ metadata:
 
 run:
   steps:
-    - "HMI and Development repositores should be enabled"
-    - $ sudo apertis-dev
     - "Install agl-compositor and maynard packages"
     - $ sudo apt-get install agl-compositor maynard
     - "Run agl-compositor:"