Subject: See below description

Description:
1) Previous commit has some error in dbconnect
   datatype problem in dbconnect vouchercode
2) vouchercode datatype shoild be String rather
   than Interger , correted
3) removed relativedeta becoze python-dateutil
  package is not there in android chroot
  so abtstart was not working in the tablet
  instead used timedelta from datetime