Move agent.linux.utils tests to proper location

blueprint reorganize-unit-test-tree

Change-Id: I21c07fadbe6701e4aa438c70fbf8f503b48d2f26

diff --git a/neutron/tests/unit/test_agent_linux_utils.py b/neutron/tests/unit/agent/linux/test_utils.py
similarity index 100%
rename from neutron/tests/unit/test_agent_linux_utils.py
rename to neutron/tests/unit/agent/linux/test_utils.py