Cleanup glide (#1353)

* Cleanup mentions about glide

* Don't use glide to ignore vendor directory

Since go-1.9, "./..." no longer contains the "vendor" directory.
Also, since #1305 migrated dependency management from glide to go mod,
there is no need to think about the "vendor" directory.

See: https://golang.org/doc/go1.9#vendor-dotdotdot

* go mod tidy

Jenkinsfile

@@ -6,7 +6,7 @@ goTemplate{
         githubOrganisation = 'kubernetes'
         dockerOrganisation = 'fabric8'
         project = 'kompose'
-        makeCommand = "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin:/usr/local/glide:/usr/local/:/go/bin:/home/jenkins/go/bin \
+        makeCommand = "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin:/usr/local/:/go/bin:/home/jenkins/go/bin \
                        && bash script/test/cmd/fix_detached_head.sh && make test"
       }
   }