Ticket #2626: special chars are not escaped in autocompletion of filenames.
Test case:
1. Create a file with name that contains some special chars:
touch attachment.cgi?id=564208
2. Press F6.
3. Press a. Now only the 'a' letter is in input line.
4. Press Esc Tab Enter.
5a. Input line is filled by 'attachment.cgi?id=564208'...
5b. but 'attachment.cgi\?id=564208' is expected.
6. Add 'patch_' before file name:
'patch_attachment.cgi?id=564208'.
7. Press Enter.
8a. Result: 'patch_attachment.cgiattachment.cgi?id=564208id=564208'.
8b. Expected result: 'patch_attachment.cgi?id=564208'.
Signed-off-by: Andrew Borodin <aborodin@vmail.ru>