glide.*, vendor/*: Add vendor for the test ssh client.

Also pin the version of a few packages in glide.yaml to pass the build.

Author: Yifan Gu

glide.lock

@@ -11,6 +11,9 @@ import:
 - package: github.com/ghodss/yaml
 - package: github.com/golang/glog
 - package: github.com/spf13/cobra
+  version: 4cdb38c072b86bf795d2c81de50784d9fdd6eb77
+- package: github.com/spf13/pflag
+  version: e57e3eeb33f795204c1ca35f56c44f83227c6e66
 - package: k8s.io/apimachinery
   version: 75b8dd260ef0469d96d578705a87cffd0e09dab8
   subpackages:
@@ -34,3 +37,10 @@ import:
   subpackages:
   - pkg/kubectl/cmd/util
   - pkg/kubectl/resource
+- package: golang.org/x/net
+  version: e90d6d0afc4c315a0d87a568ae68577cc15149a0
+- package: golang.org/x/crypto/
+  version: 0fe963104e9d1877082f8fb38f816fcd97eb1d10
+  subpackages:
+  - ssh
+  - ssh/agent