fix: use rpm-ostreed-automatic.service drop-in to wait for network

[fiftydinar]

For fixing this issue:
#90

"Temporary failure in name resolution"

Override the service instead of making the changes directly.

[bsherman]

I don't understand why this is adding a new file instead of modifying the existing service file.

I may truly be mistaken on this if we only currently customize the timer and not the service.

I am on mobile for a while and hard to review but I'll will check this when I'm back at the computer in a bit.

[akdev1l]

mm two thoughts:

1. does this change actually belong upstream? https://github.com/coreos/rpm-ostree/blob/main/src/daemon/rpm-ostreed-automatic.service - if the service needs that then we should also think about making a PR to rpm-ostree itself
2. We should use a systemd drop-in to avoid clobbering the whole file. We can create a file in /usr/etc/systemd/system/rpm-ostreed-automatic.service.conf.d/override.conf with just this content:

[Unit]
Wants=network-online.target
After=network-online.target

this would have the effect of only setting these two properties while leaving everything else the same as upstream

(also @bsherman I checked and indeed we only have a .timer file currently)

[bsherman]

(also @bsherman I checked and indeed we only have a .timer file currently)

Thanks for confirming, back and desk and I agree.

2. We should use a systemd drop-in to avoid clobbering the whole file.

Hmm... now I wonder why I didn't use a system drop-in for the timer itself... that seems like I messed up.