testing: fix more racy code in FakeProvisioner
testing: fix more racy code in FakeProvisioner

A lock here, a lock there...

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