hack/install_golangci.sh: check env vars

Also make it executable and `set -eo pipefail`.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

hack/install_golangci.sh

@@ -1,5 +1,17 @@
-#!/bin/bash -e
+#!/bin/bash
+
+if [ -z "$VERSION" ]; then
+	echo \$VERSION is empty
+	exit 1
+fi
+
+if [ -z "$GOBIN" ]; then
+	echo \$GOBIN is empty
+	exit 1
+fi
+
 $GOBIN/golangci-lint --version | grep $VERSION
 if [ $?  -ne 0 ]; then
+	set -e
 	curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $GOBIN v$VERSION
 fi