No action in which unknown persons were made parties defendant pursuant to the requirements of section 3538, supplemental supplement to the Code 1915, and in which notice of such action was given by publication between July 1, 1913, and July 1, 1915, for four consecutive weeks, the last publication being ten days prior to the first day of the term for which said action was brought as shown by proof on file in the office of the clerk of the court where said action was pending, shall be held ineffectual, void, or insufficient because the records fail to show that the court or judge approved said notice before publication or failed to endorse approval on said notice or failed to designate in which paper said notice should be published as required by section 3539, Code of 1897.