Remove last vestiges of _vendor directory

It got left behind because goautoneg is in mercurial, I believe.

Remove the _vendor/ directory & references to it - we have it in
vendor/ anyway.

Makefile

@@ -723,7 +723,7 @@ check-markdown-links:
 		-e LANG=en_US.UTF-8 \
 		-e LANGUAGE=en_US.UTF-8 \
 		rubygem/awesome_bot --allow-dupe --allow-redirect \
-		$(shell find $$PWD -name "*.md" -mindepth 1 -printf '%P\n' | grep -v vendor | grep -v _vendor | grep -v Changelog.md)
+		$(shell find $$PWD -name "*.md" -mindepth 1 -printf '%P\n' | grep -v vendor | grep -v Changelog.md)
 
 #-----------------------------------------------------------
 # kube-discovery

hack/dep.py

@@ -68,6 +68,5 @@
       print("[[override]]")
       print('  name = "%s"' % (dep))
       print('  revision = "%s"' % (godep_sha))
-      #print("pushd _vendor/{dep}; git fetch; git checkout {sha}; popd".format(dep=dep, sha=godep_sha))
   else:
     print("# UNKNOWN dep %s" % dep)

hack/verify-spelling.sh

@@ -25,7 +25,7 @@ GOBIN="${OUTPUT_GOBIN}" go install ./vendor/github.com/client9/misspell/cmd/miss
 mkdir -p .build/docs
 find . -type f \( -name "*.go*" -o -name "*.md*" \) -a -path "./docs/releases/*" -exec basename {} \; | \
 	xargs -I{} sh -c 'sed -e "/^\* .*github.com\/kubernetes\/kops\/pull/d" docs/releases/{} > .build/docs/$(basename {})'
-find . -type f \( -name "*.go*" -o -name "*.md*" \) -a \( -not -path "./vendor/*" -not -path "./_vendor/*" -not -path "./docs/releases/*" \) | \
+find . -type f \( -name "*.go*" -o -name "*.md*" \) -a \( -not -path "./vendor/*" -not -path "./docs/releases/*" \) | \
   sed -e /README-ES.md/d -e /node_modules/d |
 		xargs ${OUTPUT_GOBIN}/misspell -error