Remove some redundancy from some existing volume manager tests.
Remove some redundancy from some existing volume manager tests.

LaynePeng/flocker,moypray/flocker,agonzalezro/flocker,hackday-profilers/flocker,achanda/flocker,hackday-profilers/flocker,mbrukman/flocker,runcom/flocker,jml/flocker,runcom/flocker,Azulinho/flocker,AndyHuu/flocker,LaynePeng/flocker,wallnerryan/flocker-profiles,jml/flocker,wallnerryan/flocker-profiles,adamtheturtle/flocker,adamtheturtle/flocker,agonzalezro/flocker,1d4Nf6/flocker,lukemarsden/flocker,LaynePeng/flocker,lukemarsden/flocker,jml/flocker,mbrukman/flocker,moypray/flocker,lukemarsden/flocker,achanda/flocker,mbrukman/flocker,w4ngyi/flocker,adamtheturtle/flocker,w4ngyi/flocker,Azulinho/flocker,moypray/flocker,AndyHuu/flocker,Azulinho/flocker,runcom/flocker,achanda/flocker,agonzalezro/flocker,hackday-profilers/flocker,1d4Nf6/flocker,w4ngyi/flocker,1d4Nf6/flocker,wallnerryan/flocker-profiles,AndyHuu/flocker