integration: match code.Canceled in "TestV3KVInflightRangeRequests"
integration: match code.Canceled in "TestV3KVInflightRangeRequests"

Match new error codes in gRPC v1.22.0

Signed-off-by: Gyuho Lee <0fbd30d364d71722b926950b451cecd97b54fc29@amazon.com>

etcd-io/etcd,gyuho/etcd,etcd-io/etcd,etcd-io/etcd,mqliang/etcd,mqliang/etcd,coreos/etcd,gyuho/etcd,ajityagaty/etcd,mkumatag/etcd,coreos/etcd,ajityagaty/etcd,cockroachdb/etcd,mkumatag/etcd,mkumatag/etcd,li-ang/etcd,dannysauer/etcd,cockroachdb/etcd,dannysauer/etcd,li-ang/etcd,ajityagaty/etcd,rnaveiras/etcd,rnaveiras/etcd,mqliang/etcd,rnaveiras/etcd