Add go-systemd dep for CI testing

The underlying package changed and we need to depend on a specific
version now for testing with the CI

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

.travis.yml

@@ -2,13 +2,14 @@ language: go
 go:
     - 1.10.x
     - 1.11.x
-    - tip
 
 install:
-    - mkdir -p $GOPATH/src/github.com/prometheus $GOPATH/src/github.com/opencontainers
+    - mkdir -p $GOPATH/src/github.com/prometheus $GOPATH/src/github.com/opencontainers $GOPATH/src/github.com/coreos $GOPATH/src/github.com/godbus
     - cd $GOPATH/src/github.com/opencontainers && git clone https://github.com/opencontainers/runtime-spec && cd runtime-spec && git checkout fa4b36aa9c99e00c2ef7b5c0013c84100ede5f4e
+    - cd $GOPATH/src/github.com/coreos && git clone https://github.com/coreos/go-systemd && cd go-systemd && git checkout 48702e0da86bd25e76cfef347e2adeb434a0d0a6
+    - cd $GOPATH/src/github.com/godbus && git clone https://github.com/godbus/dbus && cd dbus && git checkout c7fdd8b5cd55e87b4e1f4e372cdb1db61dd6c66f
     - cd $GOPATH/src/github.com/containerd/cgroups
-    - go get -t ./...
+    - go get -d -t ./...
     - go get -u github.com/vbatts/git-validation
     - go get -u github.com/kunalkushwaha/ltag