To reproduce:

- Go into some directory with write permissions (eg /tmp)
- do # mkdir foo bar bar/boz bar/baz-$'\n'.
- do # cd foo
- enter 'ls -la ../ba' and press <tab> to complete entries in there

Expected result:
I get a list of entries, with "boz" and "baz-?" to choose from.

Actual result:
<tab> removes the whole parameter, and I end up with "ls -la .".


I know that a newline in a filename is a bad thing (I had a bug in a
"find -printf" line ;), but still it shouldn't break that way.