Check for vet errors in all directories.

Author: rjnagal

.travis.yml

@@ -13,4 +13,4 @@ script:
  - export PATH=$PATH:$HOME/gopath/bin
  - godep go test -v -race -test.short github.com/google/cadvisor/...
  - godep go build github.com/google/cadvisor
- - go vet github.com/google/cadvisor
+ - go vet github.com/google/cadvisor/...