Handle SSH-key options with spaces
Handle SSH-key options with spaces

The options given for an SSH key may contain spaces (inside a quoted
string), and escaped quotes. As stated in `man sshd 8`:

> The options (if present) consist of comma-separated option
> specifications. No spaces are permitted, except within double quotes.

and

> command="command"
>     Specifies that the command is executed whenever this key is used
>     for authentication. [...]
>     A quote may be included in the command by quoting it with a
>     backslash.

The current patch fixes a big where options containing spaces or escaped
quotes were not handled correctly, resulting in an Exception:

    ValueError: Could not parse key, too many fields

mbr/sshkeys