qemu: misc fixes for new qemu release

- Ensure qemu is built in same ubuntu distro as where it is run
- Add new libslirp-dev dep to docker container that executes qemu

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: Iaa58d097de0377e4bb5ee229c5ec267ebe4565a7
2 files changed