openssl@1.1: make keg_only on Linux

[cho-m]

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Experimenting on what is broken. Probably won't work yet.

Progress on migration on non-deprecated formulae (2022-01-06):

 306 openssl@1.1
 186 openssl@3

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Mainly want to align the alias and symlink. Currently openssl@3 is aliased (openssl) but openssl@1.1 is symlinked.

This makes it less ideal compared to how we handle this for python where we can just do something like uses_from_macos <alias> and know that corresponding one will have executables available on PATH.

Right now, we need to do depends_on "openssl@1.1" or manually manipulate PATH to guarantee that the command openssl will be available.

[dawidd6]

Progress on migration on non-deprecated formulae (2022-01-06):

I guess you mistyped the year 😄

[carlocab]

Merged to openssl-migration-staging in #134234.