While the field in the Go struct is named `NanoCPUs`, it has a JSON label to
use `NanoCpus`, which was added in the original pull request (not clear what
the reason was); 846baf1fd3efcbfbf9d3eb99e436ca9a59d3e185

Some notes:

- Golang processes field names case-insensitive, so when *using* the API,
both cases should work, but when inspecting a container, the field is
returned as `NanoCpus`.
- This only affects Containers.Resources. The `Limits` and `Reservation`
for SwarmKit services and SwarmKit "nodes" do not override the name
for JSON, so have the canonical (`NanoCPUs`) casing.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 2bd46ed7e5a016f21b9259cec269340420fa7a63)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>