Set flag on RSA keys of deprecated RSA SHA1 support when loading
keys based on server version of the transport. This ensures keys
are properly flagged. Flag name has been updated to provide context
on usage.
Version matching on the OpenSSH server version has also been updated
to handle customized naming in the version string (as seen in the
Windows port) and to properly handle when no match is found.
Fixes#12344#12408#12381
46aca8be5a