debinstall #4900 ldi upload exception [resolved]

Would be nicer to output an error message instead of crashing.

[DEBUG   ] debinstall.upload: value for check_signature: yes
Traceback (most recent call last):
 File "<string>", line 1, in ?
 File "/usr/lib/python2.4/site-packages/debinstall/ldi.py", line 50, in run
   run(options, args, parser)
 File "/usr/lib/python2.4/site-packages/debinstall/command.py", line 55, in run
   self.process()
 File "/usr/lib/python2.4/site-packages/debinstall/ldi.py", line 182, in process
   self._check_signatures(changes_files)
 File "/usr/lib/python2.4/site-packages/debinstall/ldi.py", line 162, in _check_signatures
   Changes(filename).check_sig(failed)
 File "/usr/lib/python2.4/site-packages/debinstall/debfiles.py", line 28, in __init__
   self.changes = deb822.Changes(open(filename))
IOError: [Errno 21] Is a directory
prioritynormal
typebug
done in2.2.0
load0.000
load left0.000
closed by<not specified>