Revert formatting of error codes
Revert formatting of error codes

In a prior change, reformatting of the errors codes within the
specification changed their values from positive to negative integers.

Signed-off-by: Caleb Hyde <78eaef61e3b9bca971da448625e5ad5e8af777c7@gmail.com>

containernetworking/cni,appc/cni,appc/cni,containernetworking/cni