[Libguestfs] Returning list of backends through the API

[Richard W.M. Jones]

Pino, you asked on IRC about an API to return a list of backends
through the API.

If this is for testing, you could add a debug-* API to do it.  These
are not part of the specified API and so we can change or remove them
at any time.

A canonical example of this is "debug-drives" which is used in various
guestfish tests, eg:

https://github.com/libguestfs/libguestfs/blob/master/fish/test-add-domain.sh#L71

I have changed the output of this API several times and we could
remove it entirely in future.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org