BUG/MINOR: ssl: fix syntax in config error message

Some error messages about server lines had a confusing '|' instead
of '[' to delimit the config file name.
MEDIUM: ssl: Use ALPN support as it will be available in OpenSSL 1.0.2

The current ALPN support is based on custom OpenSSL patches. These are
however not the same as what has landed on OpenSSL:

http://git.openssl.org/gitweb/?p=openssl.git;a=commit;h=6f017a8f9db3a79f3a3406cf8d493ccd346db691

This patch change the code so it supports ALPN as it will be part of
OpenSSL.