PostgreSQL: conditional installation of PL/pgSQL.

This is required, because starting with PostgreSQL 9.0, PL/pgSQL
language is installed by default and database returns error when
we try to install it again.

Change-Id: I59aa8860bed27165a07e6fde80f6f873a3e90bd9
Signed-off-by: Piotr Sikora <piotr.sikora@frickle.com>
1 file changed