Fix tls-min-version= being ignored

Fix tls-min-version= being ignored

Audit required change to make PeerOptions::parse() call
parseOptions() when 'options=' altered sslOptions instead of
delaying the parse to context creation.
This missed the fact that for GnuTLS the tlsMinVersion was
also updating the sslOptions string rather than the
parsedOptions variable later in the configuration process.

Call parseOptions() to reset the parsedOptions value whenever
sslOptions string is altered.