Update of netlink version

This is required for
https://github.com/containernetworking/cni/issues/251 because version of
netlink used doesn't support creating tap devices.

vendor/github.com/vishvananda/netlink/.travis.yml

@@ -1,3 +1,8 @@
 language: go
+before_script:
+  # make sure we keep path in tact when we sudo
+  - sudo sed -i -e 's/^Defaults\tsecure_path.*$//' /etc/sudoers
+  # modprobe ip_gre or else the first gre device can't be deleted
+  - sudo modprobe ip_gre
 install:
-      - go get github.com/vishvananda/netns
+  - go get github.com/vishvananda/netns