MINOR: peers: Make outgoing connection to SSL/TLS peers work.

MINOR: peers: Make outgoing connection to SSL/TLS peers work.

This patch adds pointer to a struct server to peer structure which
is initialized after having parsed a remote "peer" line.

After having parsed all peers section we run ->prepare_srv to initialize
all SSL/TLS stuff of remote perr (or server).

Remaining thing to do to completely support peer protocol over SSL/TLS:
make "bind" keyword be supported in "peers" sections to make SSL/TLS
incoming connections to local peers work.

May be backported to 1.5 and newer.