storage: For FS pool check for properly formatted target volume
storage: For FS pool check for properly formatted target volume

Prior to starting up, let's be sure the target volume device is
formatted as we expect; otherwise, inhibit the start.

Signed-off-by: John Ferlan <87558058f6f829e5ec976c8ef960720af4ff9c7d@redhat.com>

VenkatDatta/libvirt,jardasgit/libvirt,olafhering/libvirt,zippy2/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,eskultety/libvirt,libvirt/libvirt,libvirt/libvirt,libvirt/libvirt,datto/libvirt,eskultety/libvirt,eskultety/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,andreabolognani/libvirt,jardasgit/libvirt,jfehlig/libvirt,andreabolognani/libvirt,jfehlig/libvirt,olafhering/libvirt,fabianfreyer/libvirt,crobinso/libvirt,andreabolognani/libvirt,jardasgit/libvirt,nertpinx/libvirt,nertpinx/libvirt,olafhering/libvirt,jfehlig/libvirt,crobinso/libvirt,eskultety/libvirt,taget/libvirt,taget/libvirt,jfehlig/libvirt,datto/libvirt,taget/libvirt,nertpinx/libvirt,olafhering/libvirt,VenkatDatta/libvirt,taget/libvirt,zippy2/libvirt,jardasgit/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,datto/libvirt,fabianfreyer/libvirt,VenkatDatta/libvirt,datto/libvirt,nertpinx/libvirt,crobinso/libvirt,fabianfreyer/libvirt,eskultety/libvirt,crobinso/libvirt,libvirt/libvirt,datto/libvirt,VenkatDatta/libvirt,zippy2/libvirt,taget/libvirt,zippy2/libvirt,fabianfreyer/libvirt