Propagate return code

Previously the results were only being printed, but the return code
for the checks wasn't propagated up.

oslo_upgradecheck/__main__.py

@@ -14,6 +14,8 @@
 
 """Example CLI command for running upgrade checks"""
 
+import sys
+
 from oslo_upgradecheck import upgradecheck
 
 
@@ -33,8 +35,8 @@ class Checks(upgradecheck.UpgradeCommands):
 
 def main():
     inst = Checks()
-    upgradecheck.main(inst.check)
+    return upgradecheck.main(inst.check)
 
 
 if __name__ == '__main__':
-    main()
+    sys.exit(main())

oslo_upgradecheck/tests/test_upgradecheck.py

@@ -77,4 +77,5 @@ class TestMain(base.BaseTestCase):
         mock_argv = ['test-status', 'upgrade', 'check']
         with mock.patch.object(sys, 'argv', mock_argv, create=True):
             inst = TestCommands()
-            upgradecheck.main(inst.check)
+            result = upgradecheck.main(inst.check)
+            self.assertEqual(upgradecheck.UpgradeCheckCode.FAILURE, result)

oslo_upgradecheck/upgradecheck.py

@@ -148,4 +148,4 @@ def main(check_callback):
     conf.register_cli_opt(opt)
     conf(sys.argv[1:])
 
-    conf.category.action_fn()
+    return conf.category.action_fn()