app: fix shadowing bug in FakeQueueServer
app: fix shadowing bug in FakeQueueServer

This may fix issue #221. Not sure, may dive in this issue later.

RichardKnop/tsuru,jblancett/tsuru,guilhermebr/tsuru,cgvarela/tsuru,4eek/tsuru,mderaldo/tsuru,gwmoura/tsuru,RichardKnop/tsuru,kgrvamsi/tsuru,4eek/tsuru,tsuru/tsuru,tuxmonteiro/tsuru,guilhermebr/tsuru,jblancett/tsuru,mderaldo/tsuru,4eek/tsuru,ggarnier/tsuru,hcxiong/tsuru,mderaldo/tsuru,kgrvamsi/tsuru,tsuru/tsuru,gciotta/tsuru,guilhermebr/tsuru,firebitsbr/tsuru,ArxdSilva/tsuru,guilhermebr/tsuru,ArxdSilva/tsuru,tuxmonteiro/tsuru,ggarnier/tsuru,gwmoura/tsuru,cgvarela/tsuru,cezarsa/tsuru,ggarnier/tsuru,RichardKnop/tsuru,Endika/tsuru,tsuru/tsuru,cgvarela/tsuru,ArxdSilva/tsuru,tsuru/tsuru,firebitsbr/tsuru,hcxiong/tsuru,cezarsa/tsuru,gciotta/tsuru,ArxdSilva/tsuru,firebitsbr/tsuru,Endika/tsuru,hugoantunes/tsuru,cezarsa/tsuru,tuxmonteiro/tsuru,hugoantunes/tsuru,hcxiong/tsuru,Endika/tsuru,cezarsa/tsuru,gciotta/tsuru,jblancett/tsuru,ggarnier/tsuru,kgrvamsi/tsuru,gwmoura/tsuru