openssh

Running a build through the RHEL OSCI reveals some possible shortcomings
of the original design:

- Custom macros using %__gpg may now easily break if the Sequoia backend
  is installed, such as those overriding %__gpg_sign_cmd where %__gpg is
  typically the first argument, followed by CLI options only known to
  GnuPG.  This is exactly the case with some of our Beaker tests.

- Some tests attempt to install both subpackages directly with dnf which
  obviously fails as they conflict with each other.  This is just a test
  issue, though.

Therefore, the boolean dependency in rpm-sign-libs declaring that both
implementations are equally compatible is just wrong, until we can prove
otherwise, by making the CI tests pass, for starters.

Drop the Sequoia subpackage for now.  This is less drastic than a full
revert since the actual GnuPG split-off is still reasonable on its own.
We can always add Sequoia support back later, once we figure out the
above issues.

Related: RHEL-56363