Fix RemoveResourceFromJid()
Fix RemoveResourceFromJid()

Both @ and / are valid in the resource part.  JIDs with a resource but without @ are also valid.
Test cases:
 RemoveResourceFromJid("foo@bar/foo@bar/foo") == "foo@bar"
 RemoveResourceFromJid("bar/foo@bar/foo") == "bar"
youngtrips/xmpp,GeertJohan/xmpp,tam7t/xmpp,rakoo/xmpp,frankbb/xmpp,psywolf/xmpp,shizeeg/xmpp