perf scripts python: export-to-postgresql.py: Add support for pyside2

pyside2 is the future for pyside support.

Note pyside use Qt4 whereas pyside2 uses Qt5.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190412113830.4126-6-adrian.hunter@intel.com


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