lxd/operations/operations: Renames WaitFinal to Wait, and adds context support
lxd/operations/operations: Renames WaitFinal to Wait, and adds context support

And replaces chanDone with cancel.Canceller.

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

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