[Koha] git revert

Respected All Just upgraded the Koha ver through git and facing the error Can't call method "cookie" on an undefined value at /usr/share/koha/lib/C4/Templates.pm line 323. gone through the yesterday's solution of koha forum but not successful. Kindly guide me for git revert.(exact command) -- Thanks and Regards Sandeep Bhavsar Librarian Dr.V.N.Bedekar Institute of Management Studies Thane(W) 400601 MUMBAI. INDIA @@@@@@@@@@@@@@@@@@@@@@@@@@ email : sandeep.bhavsar@gmail.com Mob : 9029 345777 elibrary :http://www.vpmthane.org/im/elib/main.htm @@@@@@@@@@@@@@@@@@@@@@@@@@