test-import-duplicity: use install tree for data
test-import-duplicity: use install tree for data

Use a stable "make install" tree for the backup data, and test the
restoration via compare-trees instead of diff.

Signed-off-by: Rob Browning <1dc5917c2adeeba13d1ef33dbb40691a1b67cc65@defaultvalue.org>
Tested-by: Rob Browning <1dc5917c2adeeba13d1ef33dbb40691a1b67cc65@defaultvalue.org>

gevaerts/bup,tjanez/bup,tjanez/bup,mhoeher/bup,tjanez/bup,jbaber/bup,tjanez/bup,jbaber/bup,gevaerts/bup,jbaber/bup,ToxicFrog/bup,ToxicFrog/bup,mhoeher/bup,gevaerts/bup,pombredanne/bup,tjanez/bup,mhoeher/bup,jbaber/bup,mhoeher/bup,jbaber/bup,gevaerts/bup,pombredanne/bup,ToxicFrog/bup,pombredanne/bup,pombredanne/bup,ToxicFrog/bup,gevaerts/bup,tjanez/bup,pombredanne/bup,mhoeher/bup,jbaber/bup,mhoeher/bup,pombredanne/bup,ToxicFrog/bup