MEDIUM: checks: Implement ssl-hello check using tcp-check rules

MEDIUM: checks: Implement ssl-hello check using tcp-check rules

A shared tcp-check ruleset is now created to support ssl-hello check. This way
no extra memory is used if several backends use a ssl-hello check.

The following sequence is used :

    tcp-check send-binary SSLV3_CLIENT_HELLO log-format

    tcp-check expect rbinary "^1[56]" min-recv 5 \
        error-status "L6RSP" tout-status "L6TOUT"

SSLV3_CLIENT_HELLO is a log-format hexa string representing a SSLv3 CLIENT HELLO
packet. It is the same than the one used by the old ssl-hello except the sample
expression "%[date(),htonl,hex]" is used to set the date field.