sos: fixing report generation on sos < 3.0

Fixing sos report generation on sos < 3.0
for PostgreSQL logs

Change-Id: I360a56a8902c1c13bc0eec3aeda66cfa5c0cab42
Bug-Url: https://bugzilla.redhat.com/1115963
Signed-off-by: Simone Tiraboschi <stirabos@redhat.com>
(cherry picked from commit 4b1bc356e42ba2294056a943b80601d8772515bd)