Fix a bug in TeeInput: socket_drained? should return true if and only if @socket is nil
Fix a bug in TeeInput: socket_drained? should return true if and only if @socket is nil

phusion/passenger,kewaunited/passenger,kewaunited/passenger,cgvarela/passenger,kewaunited/passenger,clemensg/passenger,pkmiec/passenger,jawj/passenger,kewaunited/passenger,cgvarela/passenger,clemensg/passenger,bf4/passenger,cgvarela/passenger,antek-drzewiecki/passenger,bf4/passenger,pkmiec/passenger,cgvarela/passenger,jawj/passenger,clemensg/passenger,bf4/passenger,phusion/passenger,cgvarela/passenger,jawj/passenger,cgvarela/passenger,bf4/passenger,phusion/passenger,clemensg/passenger,pkmiec/passenger,phusion/passenger,kewaunited/passenger,jawj/passenger,antek-drzewiecki/passenger,kewaunited/passenger,clemensg/passenger,clemensg/passenger,phusion/passenger,cgvarela/passenger,antek-drzewiecki/passenger,clemensg/passenger,jawj/passenger,phusion/passenger,jawj/passenger,antek-drzewiecki/passenger,pkmiec/passenger,pkmiec/passenger,clemensg/passenger,jawj/passenger,phusion/passenger,bf4/passenger,antek-drzewiecki/passenger,antek-drzewiecki/passenger,antek-drzewiecki/passenger,cgvarela/passenger,pkmiec/passenger,kewaunited/passenger,pkmiec/passenger,phusion/passenger,bf4/passenger,antek-drzewiecki/passenger,kewaunited/passenger,bf4/passenger