The set -x has produced 6 identical log strings every time the
log_backup_error_exit function is called. Prometheus is using
the occurrence and number of some logs over a period of time to
evaluate database backup failure or not. Only one log should be
generated when a particular database backup scenario failed.
Upon discussion with database backup and restore SME, it is
recommended to remove the set -x once and for all.
Change-Id: I846b5c16908f04ac40ee8f4d87d3b7df86036512
2fc1ce4a14