bash-completion: upgrade 2.13.0 -> 2.14.0

Changelog:
=============
* _comp_{compgen,xfunc}:** use 'declare -F --' for arbitrary funcs
* _comp_{load,realcommand}:** handle option-like command name
* available_interfaces:** strip only trailing colon from entries
* bash_completion,conftest:** use 'complete -p --' for arbitrary cmds
* fio:** engines completion
* ip:** Complete link change as well as set
* ip:** Don't stop at proxy and nomaster in neigh
* scp remote_files:** do not filter generated paths with "$cur"
* scp remote_files:** localize variable 'cur'
* ssh-keygen:** handling of bundled short options
* ssh-keygen:** make work with custom IFS
* ssh-keygen:** suggest -O arg completions depending on mode
* use -- to pass arbitrary cmdnames to '_comp_load'
* use 'pathcmd=$(type -P -- "$1")' for arbitrary cmds

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>