Fix errors on import with service tags

When skips were added to service tags the CONF check was being
evaluated at import. This will cause an exception when there is
no config file. This commit fixes the issue by moving the config
eval inside the decorator wrapper so that it is only done at run
time.

Change-Id: I4127e2b837e103a8e0c24b324458bee97a2326ec
Merge "Fix errors on import with service tags"