Fix double puppeting.

This was caused by some early attempts at not replaying messages. That was
fixed by tracking messages explicitly but these early returns with no logging
were never removed.

Fixes #23

bridge/puppet.go

@@ -153,7 +153,7 @@ func (p *Puppet) DefaultIntent() *appservice.IntentAPI {
 }
 
 func (p *Puppet) IntentFor(portal *Portal) *appservice.IntentAPI {
-	if p.customIntent == nil || portal.Key.Receiver == p.ID {
+	if p.customIntent == nil {
 		return p.DefaultIntent()
 	}