Remove unavailable goop, b1nzy says it'd never happen.

state.go

@@ -99,12 +99,6 @@ func (s *State) GuildAdd(guild *Guild) error {
 	}
 
 	if g, ok := s.guildMap[guild.ID]; ok {
-		// The guild already exists in state.
-		if guild.Unavailable {
-			// If the new guild is unavailable, just update the `unavailable` property on the
-			// current guild.
-			g.Unavailable = guild.Unavailable
-		} else {
 		// We are about to replace `g` in the state with `guild`, but first we need to
 		// make sure we preserve any fields that the `guild` doesn't contain from `g`.
 		if guild.Roles == nil {
@@ -126,7 +120,6 @@ func (s *State) GuildAdd(guild *Guild) error {
 			guild.VoiceStates = g.VoiceStates
 		}
 		*g = *guild
-		}
 		return nil
 	}