Make sure multiple calls to ShutdownQueue don't result in badness
Make sure multiple calls to ShutdownQueue don't result in badness

mms-/Akavache,ghuntley/AkavacheSandpit,kmjonmastro/Akavache,christer155/Akavache,MarcMagnin/Akavache,bbqchickenrobot/Akavache,gimsum/Akavache,jcomtois/Akavache,shana/Akavache,Loke155/Akavache,shiftkey/Akavache,PureWeen/Akavache,akavache/Akavache,martijn00/Akavache,shana/Akavache,MathieuDSTP/MyAkavache