cast bool to str for runner env

It appears this was causing a fatal error for runner

awx/main/tasks/jobs.py

@@ -1054,7 +1054,7 @@ class RunProjectUpdate(BaseTask):
         env['TMP'] = settings.AWX_ISOLATION_BASE_PATH
         env['PROJECT_UPDATE_ID'] = str(project_update.pk)
         if settings.GALAXY_IGNORE_CERTS:
-            env['ANSIBLE_GALAXY_IGNORE'] = True
+            env['ANSIBLE_GALAXY_IGNORE'] = str(True)
 
         # build out env vars for Galaxy credentials (in order)
         galaxy_server_list = []

awx/main/tests/unit/test_tasks.py

@@ -1346,7 +1346,7 @@ class TestProjectUpdateGalaxyCredentials(TestJobExecution):
         task.instance = project_update
         env = task.build_env(project_update, private_data_dir)
         if ignore:
-            assert env['ANSIBLE_GALAXY_IGNORE'] is True
+            assert env['ANSIBLE_GALAXY_IGNORE'] == 'True'
         else:
             assert 'ANSIBLE_GALAXY_IGNORE' not in env