After failed transfers, ftps/lftp tries to remove '' on backend

[Eugene Crosser]

duplicity 0.6.19
Python 2.6.6
LFTP version is 4.0.6
Debian 6.0.5

After (apparently) connectivity problems, the local cache ends with .part files in it. When it happens, subsequent cleanup operation fails "forever" trying to remove file named '' (empty name) on the backend:

# duplicity cleanup --force $DEST
LFTP version is 4.0.6
Local and Remote metadata are synchronized, no sync needed.
Warning, found the following local orphaned signature files:
duplicity-new-signatures.20120606T022530Z.to.20120607T022522Z.sigtar.part
duplicity-new-signatures.20120607T022522Z.to.20120608T022539Z.sigtar.part
Warning, found the following orphaned backup file:
[duplicity-inc.20120607T022522Z.to.20120608T022539Z.manifest.part]
Last full backup date: Sun Jun 3 06:25:24 2012
Deleting these files from backend:
duplicity-new-signatures.20120606T022530Z.to.20120607T022522Z.sigtar.part
duplicity-new-signatures.20120607T022522Z.to.20120608T022539Z.sigtar.part
Running 'lftp -c 'source /tmp/duplicity-0An1ir-tempdir/mkstemp-iQNUTk-1;cd 'backup/cahost';rm '' failed with code 1 (attempt #1)
Error is:
Usage: rm [-r] [-f] files...
[...]
Giving up trying to execute 'lftp -c 'source /tmp/duplicity-0An1ir-tempdir/mkstemp-iQNUTk-1;cd 'backup/cahost';rm '' after 5 attempts
BackendException: Error running 'lftp -c 'source /tmp/duplicity-0An1ir-tempdir/mkstemp-iQNUTk-1;cd 'backup/cahost';rm ''

Removing the *.part files from the local cache rectifies the problem.

[jno (jnoster)]

This is one of possible reasons that make the duplicity to "remove" empty filenames.
So, bug #1104069 is a bit more "generic".