SPEC: put Slurm version in RPM release

[kcgthb]

Add the Slurm version the RPM has been compiled with in the package name.

The main motivation is to be able to tell from the RPM version which version of Slurm the DRMAA package was built against, and facilitate upgrades when the plugin must be rebuilt for newer Slurm versions.

[natefoo]

I went around in circles when adding the spec trying to figure out the best way to do this. I think this won't force reinstallation when you change Slurm versions but it would at least make it more obvious what's going on to the admin?

[kcgthb]

Yes, that won't force reinstallation when the Slurm version is upgraded (and I can't think of a good way to create a dependency that would do this, esp. since only major Slurm versions matter), but that should make things more visible for the admin, that's the idea.
Thanks for approving the change!

[natefoo]

Thanks @kcgthb!