vendor.conf: Bump containerd/cgroups to 77e62851

vendor.conf has been pinned at containerd/cgroups@7a5fdd83 (Merge pull
request #26 from onorua/error-ignore-example, 2017-08-24) since libpod
forked from CRI-O with a031b83 (Initial checkin from CRI-O repo,
2017-11-01).  The content in vendor/github.com/containerd/cgroups was
bumped to containerd/cgroups@77e62851 (Use /proc/diskstats to get
device names, 2018-01-31) in ae89dc2 (Update containerd/cgroups repo
fix perf issue, 2018-02-01, #284), but ae89dc2 forgot to update
vendor.conf.  With this commit:

  $ vndr github.com/containerd/cgroups

no longer changes anything under vendor/github.com/containerd/cgroups.

Signed-off-by: W. Trevor King <[email protected]>

Closes: #749
Approved by: mheon

Author: wking

vendor.conf

@@ -6,7 +6,7 @@ github.com/Microsoft/hcsshim 43f9725307998e09f2e3816c2c0c36dc98f0c982
 github.com/blang/semver v3.5.0
 github.com/boltdb/bolt master
 github.com/buger/goterm 2f8dfbc7dbbff5dd1d391ed91482c24df243b2d3
-github.com/containerd/cgroups 7a5fdd8330119dc70d850260db8f3594d89d6943
+github.com/containerd/cgroups 77e628511d924b13a77cebdc73b757a47f6d751b
 github.com/containerd/continuity master
 github.com/containernetworking/cni v0.6.0
 github.com/containernetworking/plugins master