integration: adjust tests for omitted "OnBuild"

The Docker API may either return an empty "OnBuild" or omit the
field altogether if it's not set.

Adjust the tests to make either satisfy the test.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Author: thaJeztah

tests/integration/api_build_test.py

@@ -275,7 +275,7 @@ def test_build_container_with_target(self):
             pass
 
         info = self.client.inspect_image('build1')
-        assert not info['Config']['OnBuild']
+        assert 'OnBuild' not in info['Config'] or not info['Config']['OnBuild']
 
     @requires_api_version('1.25')
     def test_build_with_network_mode(self):

tests/ssh/api_build_test.py

@@ -266,7 +266,7 @@ def test_build_container_with_target(self):
             pass
 
         info = self.client.inspect_image('build1')
-        assert not info['Config']['OnBuild']
+        assert 'OnBuild' not in info['Config'] or not info['Config']['OnBuild']
 
     @requires_api_version('1.25')
     def test_build_with_network_mode(self):