Bz1146694 <oo-install> - use TMPDIR instead of hardcodded tmp

https://bugzilla.redhat.com/show_bug.cgi?id=1146694
- Change some temporary paths to honour $TMPDIR instead of hardcoded
  full path. This allows to invoke the installer with a custom tmpdir
  location. Note that $TMPDIR is used (same value) in all hosts though.
- set TMPDIR for remote commands if set