BUG/MINOR: peers: Missing initializations after peer session shutdown.

BUG/MINOR: peers: Missing initializations after peer session shutdown.

This patch fixes a bug introduced by 045e0d4 commit where it was really a bad
idea to reset the peer applet context before shutting down the underlying
session. This had as side effect to cancel the re-initializations done by
peer_session_release(), especially prevented this function from re-initializing
the current table pointer which is there to force annoucement of stick-table
definitions on when reconnecting. Consequently the peers could send stick-table
update messages without a first stick-table definition message. As this is
forbidden, this leaded the remote peers to close the sessions.