[Dovecot] dovecot 1.2.6 fails to build with openssl < 0.9.8

[Paul Howarth]

The update of ssl_proxy_get_security_string() in dovecot 1.2.6 has
broken compatibility with openssl < 0.9.8 (e.g. on RHEL4) because the
functions SSL_COMP_get_name and SSL_get_current_compression don't exist
until openssl 0.9.8 (build fails at link time due to these symbols
being unresolved). I've worked around this by reverting the function to
the 1.2.5 version for now but I think a better solution would be to
have a configure test for these functions and only include the SSL
compression details when they're available.

Cheers, Paul.