MINOR: connection: use dst addr as parameter for srv conn hash

MINOR: connection: use dst addr as parameter for srv conn hash

The destination address is used as an input to the server connection hash. The
address and port are used as separated hash inputs. Note that they are not used
when statically specified on the server line. This is only useful for dynamic
destination address.

This is typically used when the server address is dynamically set via the
set-dst action. The address and port are separated hash parameters.

Most notably, it should fixed set-dst use case (cf github issue #947).