Merge ~sylvain-pineau/checkbox-ng:build_tree_using_effective_category_id into checkbox-ng:master

[Sylvain Pineau]

This MR fixes the UI screens where the tester can pick up the tests to run using trees of jobs (ordered by categories).
Without the fix, categories overrides are not taken into account i.e job selection is inefficient.

[Sylvain Pineau (sylvain-pineau)]

tested using the snappy providers and applying the following overrides:

category_overrides:
    apply "2013.com.canonical.plainbox::suspend" to "2013.com.canonical.certification::after-suspend-.*"

self-approved

review: Approve

diff --git a/checkbox_ng/misc.py b/checkbox_ng/misc.py
index b5c06eb..dc92a37 100644
--- a/checkbox_ng/misc.py
+++ b/checkbox_ng/misc.py
@@ -157,7 +157,8 @@ class JobTreeNode:
         """
         root_node = cls()
         for job in job_list:
-            cat_name = sa.get_category(job.category_id).tr_name()
+            cat_id = sa.get_job_state(job.id).effective_category_id
+            cat_name = sa.get_category(cat_id).tr_name()
             matches = [n for n in root_node.categories if n.name == cat_name]
             if not matches:
                 node = cls(cat_name)