Do not claim to be loading a plugin which we aren't.
Do not claim to be loading a plugin which we aren't.

I had forgotten to update my config.toml after #994 and was very confused by:

INFO[0000] starting containerd boot...                   module=containerd
INFO[0000] starting debug API...                         debug="/run/containerd/debug.sock" module=containerd
INFO[0000] loading plugin "io.containerd.content.v1.content"...  module=containerd type=io.containerd.content.v1
INFO[0000] loading plugin "io.containerd.snapshotter.v1.btrfs"...  module=containerd type=io.containerd.snapshotter.v1
INFO[0000] loading plugin "io.containerd.snapshotter.v1.overlayfs"...  module=containerd type=io.containerd.snapshotter.v1
INFO[0000] loading plugin "io.containerd.differ.v1.base-diff"...  module=containerd type=io.containerd.differ.v1
containerd: no plugins registered for io.containerd.snapshotter.v1

Where apparently two candidates for io.containerd.snapshotter.v1 had been
loaded but the error claimed (correctly, it turns out) that none were. With
this change instead I see:

INFO[0000] starting containerd boot...                   module=containerd
INFO[0000] starting debug API...                         debug="/run/containerd/debug.sock" module=containerd
INFO[0000] loading plugin "io.containerd.content.v1.content"...  module=containerd type=io.containerd.content.v1
INFO[0000] skipping plugin "io.containerd.snapshotter.v1.btrfs"...  module=containerd type=io.containerd.snapshotter.v1
INFO[0000] skipping plugin "io.containerd.snapshotter.v1.overlayfs"...  module=containerd type=io.containerd.snapshotter.v1
INFO[0000] loading plugin "io.containerd.differ.v1.base-diff"...  module=containerd type=io.containerd.differ.v1
containerd: no plugins registered for io.containerd.snapshotter.v1

Signed-off-by: Ian Campbell <9be92b3dbbd6611e3e4c9209fb3d04b4919e7cca@docker.com>

miaoyq/containerd,containerd/containerd,miaoyq/containerd,estesp/containerd,thaJeztah/containerd,estesp/containerd,crosbymichael/containerd,crosbymichael/containerd,hqhq/containerd,vdemeester/containerd,rajasec/containerd,AkihiroSuda/containerd,kunalkushwaha/containerd,chanezon/containerd,containerd/containerd,mikebrow/containerd,thaJeztah/containerd,kunalkushwaha/containerd,mikebrow/containerd,dmcgowan/containerd,vdemeester/containerd,dmcgowan/containerd