perf script: Fix postgresql ubuntu install instructions

The current instructions for setting up an Ubuntu system for using the
export-to-postgresql.py script are incorrect.

The instructions in the script have been updated to work on newer
versions of ubuntu.

-Add missing dependencies to apt-get command:
    python-pyside.qtsql, libqt4-sql-psql
-Add '-s' option to createuser command to force the user to be a
    superuser since the command doesn't prompt as indicated in the
    current instructions.

Tested on: Ubuntu 14.04, Ubuntu 16.04(beta)

Signed-off-by: Chris Phlipot <cphlipot0@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1461056164-14914-3-git-send-email-cphlipot0@gmail.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>