[SAC] upgraded gdal and proj4 on the adhoc vm


in fighting a OGR bug I've updated the installed versions of PROJ.4 and
GDAL on the adhoc VM to the latest semi-official packages from the
DebianGIS stack on backports.org.

"new" versions:
  gdal 1.5.4-4~bpo50+2
  proj 4.6.1-5~bpo50+1

just in case anyone needs to rebuild anything,

ps- postgres 8.3 package is still broken there.