Update fsouza/go-dockerclient

The updated dep requires adding the following new deps:

- vendor/github.com/fsouza/go-dockerclient
- vendor/golang.org/x/net

.gitmodules

@@ -124,9 +124,12 @@
 [submodule "vendor/github.com/containernetworking/cni"]
 	path = vendor/github.com/containernetworking/cni
 	url = https://github.com/containernetworking/cni
-[submodule "vendor/golang.org/x/net"]
-	path = vendor/golang.org/x/net
-	url = https://go.googlesource.com/net
 [submodule "vendor/google.golang.org/grpc"]
 	path = vendor/google.golang.org/grpc
 	url = https://github.com/grpc/grpc-go
+[submodule "vendor/github.com/docker/go-units"]
+	path = vendor/github.com/docker/go-units
+	url = https://github.com/docker/go-units
+[submodule "vendor/golang.org/x/net"]
+	path = vendor/golang.org/x/net
+	url = https://github.com/golang/net