Fix facts refreshing when refresh_type=systemd

[smortex]

@treydock reported that an invalid condition was introduced in #335.
This commit fix that.

[smortex]

@treydock can you please confirm that fix your issue?

[treydock]

I think this should work but would take me a bit of time to integrate into our GHE environment. I think this approach is better than using systemd fact since that relies on systemd module which sites without systemd may not use.

[treydock]

Verified this works on a host where systemd is the preferred method to deploy the fact refresh timer.

$ sudo facter -p service_provider
systemd

Our r10k config is using this branch and applied to host that had downgraded to 0.14.5 so nothing changed:

$ sudo puppet agent -t --noop
Info: Using environment 'dev_OMIT_11402'
Info: Retrieving pluginfacts
Info: Retrieving plugin
Info: Loading facts
Notice: Requesting catalog from OMIT
Notice: Catalog compiled by OMIT
Info: Applying configuration version 'OMIT::dev_OMIT_11402::edc5b3bc75a8e693cf1fb39f5dbaef71d714541c::::'
Notice: Applied catalog in 49.67 seconds