Merge pull request #101 from yuvipanda/forcerm

Remove intermediate containers in failed builds

repo2docker/detectors.py

@@ -420,6 +420,8 @@ class BuildPack(LoggingConfigurable):
                     'JUPYTERHUB_VERSION': self.jupyterhub_version,
                 },
                 decode=True,
+                forcerm=True,
+                rm=True
         ):
             yield line