Move subp into its own module. (#416)

This was painful, but it finishes a TODO from cloudinit/subp.py.

It moves the following from util to subp:
  ProcessExecutionError
  subp
  which
  target_path

I moved subp_blob_in_tempfile into cc_chef, which is its only caller.
That saved us from having to deal with it using write_file
and temp_utils from subp (which does not import any cloudinit things now).

It is arguable that 'target_path' could be moved to a 'path_utils' or
something, but in order to use it from subp and also from utils,
we had to get it out of utils.

1 files changed, 2 insertions, 2 deletions

diff --git a/cloudinit/config/tests/test_mounts.py b/cloudinit/config/tests/test_mounts.py
index 80b54d0f..764a33e3 100644
--- a/cloudinit/config/tests/test_mounts.py
+++ b/cloudinit/config/tests/test_mounts.py
@@ -13,12 +13,12 @@ class TestCreateSwapfile:
 
     @pytest.mark.parametrize('fstype', ('xfs', 'btrfs', 'ext4', 'other'))
     @mock.patch(M_PATH + 'util.get_mount_info')
-    @mock.patch(M_PATH + 'util.subp')
+    @mock.patch(M_PATH + 'subp.subp')
     def test_happy_path(self, m_subp, m_get_mount_info, fstype, tmpdir):
         swap_file = tmpdir.join("swap-file")
         fname = str(swap_file)
 
-        # Some of the calls to util.subp should create the swap file; this
+        # Some of the calls to subp.subp should create the swap file; this
         # roughly approximates that
         m_subp.side_effect = lambda *args, **kwargs: swap_file.write('')