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

script/check-vendor.sh

@@ -1,69 +0,0 @@
-#!/bin/bash
-
-# Copyright 2017 The Kubernetes Authors All rights reserved.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-# Check if there are nested vendor dirs inside Kompose vendor.
-# All dependencies should be flattened and there shouldn't be vendor in inside vendor.  
-
-function check_nested_vendor() {
-    echo "Checking for nested vendor dirs"
-
-    # count all vendor directories inside Kompose vendor
-    NO_NESTED_VENDORS=$(find vendor/ -type d | sed 's/^[^/]*.//g' | grep -E "vendor$" | grep -v _vendor | wc -l)
-    
-    if [ $NO_NESTED_VENDORS -ne 0 ]; then
-        echo "ERROR"
-        echo "  There are $NO_NESTED_VENDORS nested vendors in Kompose vendor directory"
-        echo "  Please run 'glide update --strip-vendor'"
-        return 1
-    else
-        echo "OK"
-        return 0
-    fi
-}
-
-
-# Check if Kompose vendor directory was cleaned by glide-vc  
-function check_glide-vc() {
-    echo "Checking if vendor was cleaned using glide-vc."
-
-    # dry run glide-vc and count how many could be deleted. 
-    NO_DELETED_FILES=$(glide-vc --only-code --no-tests --dryrun | wc -l)
-    
-    if [ $NO_DELETED_FILES -ne 0 ]; then
-        echo "ERROR"
-        echo "  There are $NO_DELETED_FILES files that can be deleted by glide-vc."
-        echo "  Please run 'glide-vc --only-code --no-tests'" 
-        return 1
-    else
-        echo "OK"
-        return 0
-    fi
-}
-
-
-# Run both checks and exit report fail exit code if one of them failed.
-check_nested_vendor
-VENDOR_CHECK=$?
-
-check_glide-vc
-VC_CHECK=$? 
-
-if [ $VENDOR_CHECK -eq 0 ] && [ $VC_CHECK -eq 0 ]; then
-    exit 0
-else
-    exit 1
-fi
-