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, 3 insertions, 2 deletions

diff --git a/cloudinit/net/tests/test_init.py b/cloudinit/net/tests/test_init.py
index 835ed807..1c0a16a8 100644
--- a/cloudinit/net/tests/test_init.py
+++ b/cloudinit/net/tests/test_init.py
@@ -14,7 +14,8 @@ import requests
 import cloudinit.net as net
 from cloudinit import safeyaml as yaml
 from cloudinit.tests.helpers import CiTestCase, HttprettyTestCase
-from cloudinit.util import ProcessExecutionError, ensure_file, write_file
+from cloudinit.subp import ProcessExecutionError
+from cloudinit.util import ensure_file, write_file
 
 
 class TestSysDevPath(CiTestCase):
@@ -541,7 +542,7 @@ class TestInterfaceHasOwnMAC(CiTestCase):
             net.interface_has_own_mac('eth1', strict=True)
 
 
-@mock.patch('cloudinit.net.util.subp')
+@mock.patch('cloudinit.net.subp.subp')
 class TestEphemeralIPV4Network(CiTestCase):
 
     with_logs = True