Merge pull request #7927 from hashicorp/fix_googlecompute_crash_7921

code changed recently so that sometimes the conf is nil.

builder/googlecompute/driver_gce.go

@@ -41,7 +41,7 @@ func NewClientGCE(conf *jwt.Config) (*http.Client, error) {
 	var client *http.Client
 
 	// Auth with AccountFile first if provided
-	if len(conf.PrivateKey) > 0 {
+	if conf != nil && len(conf.PrivateKey) > 0 {
 		log.Printf("[INFO] Requesting Google token via account_file...")
 		log.Printf("[INFO]   -- Email: %s", conf.Email)
 		log.Printf("[INFO]   -- Scopes: %s", DriverScopes)