This fixes a bug under bash-4 where completing:
scp -F 'spaced conf' <TAB>
causes `dequote' to yield errors:
bash: eval: line 1: unexpected EOF while looking for matching `''
bash: eval: line 2: syntax error: unexpected end of file
The bug occurs because of a bug in bash-4.0, where quoted words are split
unintended, see: http://www.mail-archive.com/bug-bash@gnu.org/msg06095.html
Workaround is now to silence `dequote' in case of errors and wait for bash-4 to
be fixed...
1be84710d2