Do not use goimports in hack/update-generated-conversions.sh

Stop depending on an external binary needing to be on people's system.
Use the code directly.

hack/after-build/update-generated-conversions.sh

@@ -33,26 +33,15 @@ function generate_version() {
 
 	sed 's/YEAR/2015/' hack/boilerplate/boilerplate.go.txt > "$TMPFILE"
 	cat >> "$TMPFILE" <<EOF
-package ${version##*/}
+// DO NOT EDIT. THIS FILE IS AUTO-GENERATED BY \$KUBEROOT/hack/update-generated-conversions.sh
 
-// AUTO-GENERATED FUNCTIONS START HERE
 EOF
 
   "${genconversion}" -v "${version}" -f - >>  "$TMPFILE"
 
-	cat >> "$TMPFILE" <<EOF
-// AUTO-GENERATED FUNCTIONS END HERE
-EOF
-
-	goimports -w "$TMPFILE"
 	mv "$TMPFILE" "pkg/${version}/conversion_generated.go"
 }
 
-if ! which goimports >/dev/null; then
-	echo "goimports not in path, run go get golang.org/x/tools/cmd/goimports"
-	exit 1
-fi
-
 DEFAULT_VERSIONS="api/v1 expapi/v1"
 VERSIONS=${VERSIONS:-$DEFAULT_VERSIONS}
 for ver in $VERSIONS; do