Pass --python=$(PYTHON) to qemu's configure.
Fixes error:
Python not found. Use --python=/path/to/python
Signed-off-by: Christoph Egger <Christoph.Egger@amd.com> Acked-by: Ian Jackson <ian.jackson@eu.citrix.com> Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>