Move UDEVADM and SHUTDOWN definitions to runtime constants #2564

[FroggyFlox]

@phillxnet, this is another pull-request that compiles changes we discussed, hoping it'll help.

This PR moves the definitions of UDEVADM and SHUTDOWN from our Django settings to run time in the already existing system.constants.py.

Note that in Leap 15.4, we have:

rockdev:/opt/rockstor # which udevadm
/sbin/udevadm

But this is just a symlink to /usr/bin/udevadm:

rockdev:/opt/rockstor # ls -lah /sbin/udevadm
lrwxrwxrwx 1 root root 16 Apr 28 11:09 /sbin/udevadm -> /usr/bin/udevadm

/usr/bin/udevadm is also the correct path in Tumbleweed, so using this path covers both Leap and Tumbleweed.

To test:

• the branch builds successfully
• rockstor-bootstrap starts successfully
• I can access the Rockstor first login UI.

Hope this helps,

[phillxnet]

@FroggyFlox Thanks for this - much appreciated. I may loose commit attribution as a squash my current working branch but this is a great help so popping in as I go. We should hopefully have a mostly working base to push to testing and move to working from there via issue-pr sets.