hdhomerun: change ADDON_* variable names

having $ADDON_HOME replaced -n vdr / tvheadend after
sourcing userspace.driver.sh is not what we want
sundtek-mediatv: change ADDON_* variable names

having $ADDON_HOME replaced -n vdr / tvheadend after
sourcing userspace.driver.sh is not what we want
tvheadend: append LD_PRELOAD

closes #2345
sundtek-mediatv: bump
hdhomerun: bump
tvheadend: bump