Remove maybe_cleanup util function

It was used in exactly one place, and could be inlined with
minimal loss of clarity

repo2docker/app.py

@@ -35,7 +35,7 @@ from .buildpacks import (
 )
 from . import contentproviders
 from .utils import (
-    ByteSpecification, maybe_cleanup, is_valid_docker_image_name,
+    ByteSpecification, is_valid_docker_image_name,
     validate_and_generate_port_mapping, chdir
 )
 
@@ -703,9 +703,7 @@ class Repo2Docker(Application):
             else:
                 checkout_path = self.git_workdir
 
-        # keep as much as possible in the context manager to make sure we
-        # cleanup if things go wrong
-        with maybe_cleanup(checkout_path, self.cleanup_checkout):
+        try:
             self.fetch(self.repo, self.ref, checkout_path)
 
             if self.subdir:
@@ -751,6 +749,10 @@ class Repo2Docker(Application):
                         else:
                             self.log.info(json.dumps(l),
                                           extra=dict(phase='building'))
+        finally:
+            # Cheanup checkout if necessary
+            if self.cleanup_checkout:
+                shutil.rmtree(checkout_path, ignore_errors=True)
 
         if self.push:
             self.push_image()

repo2docker/utils.py

@@ -69,14 +69,6 @@ def chdir(path):
         os.chdir(old_dir)
 
 
-@contextmanager
-def maybe_cleanup(path, cleanup=False):
-    """Delete the directory at passed path if cleanup flag is True."""
-    yield
-    if cleanup:
-        shutil.rmtree(path, ignore_errors=True)
-
-
 def validate_and_generate_port_mapping(port_mapping):
     """
     Validate the port mapping list and return a list of validated tuples.