t/compare-trees: check rsync capability support correctly.
t/compare-trees: check rsync capability support correctly.

Handle older versions of rsync (where nothing was printed), and for
newer versions, check for "no FOO" rather than "FOO", since FOO will
always be listed one way or the other.

Handle ACL and xattr support independently.

Signed-off-by: Rob Browning <1dc5917c2adeeba13d1ef33dbb40691a1b67cc65@defaultvalue.org>
Tested-by: Zoran Zaric <d7dacae2c968388960bf8970080a980ed5c5dcb7@zoranzaric.de>
Reviewed-by: Zoran Zaric <d7dacae2c968388960bf8970080a980ed5c5dcb7@zoranzaric.de>

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