updated docs for Ubuntu packaging
updated docs for Ubuntu packaging

ocefpaf/pycsw,kalxas/pycsw,PublicaMundi/pycsw,ocefpaf/pycsw,kevinpdavies/pycsw,ckan-fcd/pycsw-fcd,bukun/pycsw,ingenieroariel/pycsw,ingenieroariel/pycsw,geopython/pycsw,geopython/pycsw,tomkralidis/pycsw,mwengren/pycsw,mwengren/pycsw,bukun/pycsw,ckan-fcd/pycsw-fcd,ricardogsilva/pycsw,kalxas/pycsw,bukun/pycsw,ricardogsilva/pycsw,benhowell/pycsw,tomkralidis/pycsw,rouault/pycsw,tomkralidis/pycsw,kevinpdavies/pycsw,ricardogsilva/pycsw,PublicaMundi/pycsw,benhowell/pycsw,kalxas/pycsw,rouault/pycsw,geopython/pycsw