openssl binary with OPENSSL_BIN. This will allow us to use the OPENSSL
variable from mk.conf or the make(1) command line indicating if we're
building with our without OpenSSL, and ultimately get the regress tests
working in the OPENSSL=no configuration.
OpenBSD-Regress-ID: 2d788fade3264d7803e5b54cae8875963f688c4e
allows overriding if necessary (eg in -portable where we're testing against a
specific version of OpenSSL).
OpenBSD-Regress-ID: 491f39cae9e762c71aa4bf045803d077139815c5
eliminate explicit specification of protocol in tests and
loops over protocol. We only support SSHv2 now.
Upstream-Regress-ID: 0082838a9b8a382b7ee9cbf0c1b9db727784fadd