Inconsistent error handling in the openssl init code

The errorhandling in be_tls_init(), and functions called from it, set the
appropriate elevel by the isServerStart.  ssl_protocol_version_to_openssl() is
however erroring out unconditionally with ERROR on invalid TLS versions.  The
attached patch adds isServerStart handling to the TLS version handling as well,
to make be_tls_init() consistent in its errorhandling.

cheers ./daniel