test(opennebula): remove leftover global assignment in test_find_candidates

When test_find_candidates was refactored from a try/finally pattern to
@mock.patch in d482353, the bare global assignment
`util.find_devs_with = my_devs_with` was left in by mistake. The
try/finally used to save and restore the original; without it, this
assignment leaks state and can cause order-dependent failures in other
tests. The @mock.patch decorator already patches the function correctly
and restores it after the test.

Refs GH-6810

Author: mcanevet

tests/unittests/sources/test_opennebula.py

@@ -7,7 +7,7 @@
 
 import pytest
 
-from cloudinit import atomic_helper, util
+from cloudinit import atomic_helper
 from cloudinit.sources import DataSourceOpenNebula as ds
 from tests.unittests.helpers import populate_dir
 
@@ -365,8 +365,6 @@ def my_devs_with(criteria):
             }.get(criteria, [])
 
         m_find_devs_with.side_effect = my_devs_with
-        # Signature of my_devs_with doesn't match util.find_devs_with
-        util.find_devs_with = my_devs_with  # type: ignore[assignment]
         assert ["/dev/sdb", "/dev/sr0", "/dev/vdb"] == ds.find_candidate_devs()