Refactor Google::Auth#get_application_default

lib/googleauth.rb

@@ -87,9 +87,7 @@ END
     # @param scope [string|array|nil] the scope(s) to access
     # @param options [hash] allows override of the connection being used
     def get_application_default(scope = nil, options = {})
-      creds = DefaultCredentials.from_env(scope)
-      return creds unless creds.nil?
-      creds = DefaultCredentials.from_well_known_path(scope)
+      creds = DefaultCredentials.from_env(scope) || DefaultCredentials.from_well_known_path(scope)
       return creds unless creds.nil?
       fail NOT_FOUND_ERROR unless GCECredentials.on_gce?(options)
       GCECredentials.new