ruby: add back openssl variant

[Kerilk]

Hello,

This adds back the openssl variant that was removed when older openssl versions were deprecated.
Without this option, most ruby package would fail to install since it breaks the gem utility.
Of the ruby versions that are currently supported in the package, only ruby 3.1+ are correctly building with this option enabled.

It should be possible to add support for older ruby versions since their maintenance releases got upgraded openssl support, but I think this is outside the scope of this PR.

This older pr was taking a similar approach to fixing openssl support:
#1813

[Kerilk]

I tried reproducing the ci failure, I think it could be related to the gcc 7.5.0 used.
I tried this:

spack install [email protected]
spack install [email protected]%[email protected]

But the second command has been running for an hour with no output, so I think I am doing something wrong here (I do have at least 5 compilers natively installed on the system, so that may not help the concretizer).
I'll try on one of our SLES6 systems that may still have one of these installed, and see if I can reproduce there.