[Libguestfs] [PATCH] v2v: -i vmx: Allow ssh URLs to use spaces.

In previous discussion here: https://www.redhat.com/archives/libguestfs/2017-December/thread.html#00027 we preferred to use ssh://... URLs instead of server:/path. However the URL approach had the problem that the user had to replace spaces with %20 in the paths. However since using space gives an error, we can replace spaces with %20 safely in code, thus removing one obstacle from users. Rich.