lxd/storage/drivers/utils: Extends OperationLockName to take into account content type.
lxd/storage/drivers/utils: Extends OperationLockName to take into account content type.

Also re-arranges arguments to be hierarchical and to include specific types where possible to avoid confusion.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

stgraber/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,stgraber/lxd,stgraber/lxd,atxwebs/lxd,hallyn/lxd,lxc/lxd,stgraber/lxd,lxc/lxd,hallyn/lxd,atxwebs/lxd,hallyn/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,stgraber/lxd,atxwebs/lxd,atxwebs/lxd,stgraber/lxd,lxc/lxd,hallyn/lxd