Remove expired ports:
2010-10-14 devel/p5-P4: Depends of p5-P4-Client, which is DEPRECATED.
2010-01-08 devel/p5-P4-Client: has been broken for 11 months
2010-10-14 net-p2p/btpeer: Does not build with net/Sockets and is unmaintained.
2009-07-01 net-mgmt/net-snmp4: Use net-mgmt/net-snmp port instead
2010-10-14 net/gkrellm_snmp: Depends of net-snmp4, that is deprecated also and
will be removed soon.
2010-10-14 net/Sockets-devel: Older than net/Sockets and unmaintained.