Update to 1.2.8.

Changes:
Improve handling of incorrect permissions on backup repository during
restore operation. Closes Ubuntu bug #329722. (Andrew Ferguson)

Don't crash on zlib errors. Closes Debian bug #518531. (Andrew Ferguson)

Make sticky bit warnings quieter while determining file system abilities.
Closes Savannah bug #25788. (Andrew Ferguson)

Fix situation where destination file cannot be opened because of an access
error. Thanks to Dean Cording for the bug report. (Andrew Ferguson)

Fix --compare-hash options on Windows. Thanks to Serge Zub for the fix.

(snj)