Prior to this commit, if a user set the `destination` path to include a
space, the `shell_expand_guest_path` function would remove that space
and return a partial path. This commit updates that to quote the path to
be expanded to preserve the entire path.
bunch of retires rather than a long sleep.
Add DarwinNFSMountFailed error. This might move be more appropriate at
the plugin level.
Integrate some of tvsutton's work in configure_networks to get the
implementation closer to working in both fusion and virtualbox.
Add shell_expand_guest_path capability (also copied from linux)