security/distcache: unbreak the build when using OpenSSL from ports

While appropriate --with-ssl=${OPENSSLBASE} switch is passed to the
configure script, the SSLeay_version -> OpenSSL_version adjustment
was performed not relative to ${OPENSSLINC}, which is wrong. Also,
this check cannot be executed at `post-patch' because OpenSSL from
ports is not yet available at this early stage.

PR: 236820