Where Assessing Officer completed assessment of assessee under section 143(3) and later reopened same for reason that income during year had escaped assessment and issued notice under section 148 beyond period of four years, since in facts of case there was hardly anything on record to indicate that there was failure on part of assessee to disclose truly and fully all material facts and also there was no tangible material available for purpose of issuing notice for reopening beyond period of four years, impugned notice under section 148 required to be quashed