packaging: setup: use env statement at misc in single_etl

misc stage runs also if new_database, where self._statement is not set.

Change-Id: Iaedbda91fcd055f31069bee7afab75ade5891959
Bug-Url: https://bugzilla.redhat.com/1118350
Signed-off-by: Yedidyah Bar David <didi@redhat.com>
(cherry picked from commit e74d8d8745d034d3549542bdb12f084c6878a5b6)