[Qemu-devel] qom: add test tools (resend from "qom: dynamic properties")

[Michael Roth <mdroth@linux.vnet.ibm.com>]

AFAICT tell the qom tool got dropped from Anthony's "qom: dynamic properties
and composition tree" series due to some hardcoded paths for the QMP socket.

I've since ended up adding support for user-specified paths to get them working
in my environment so I figured I'd resend to the list since I've seen others
express interest.

Only functional change for existing users would be the need to set your
QMP_SOCKET env variable to the previously hard-coded path:

mdroth@illuin:~$ qom-set -h
environment variables:
    QMP_SOCKET=<path | addr:port>
usage:
    /home/mdroth/bin/qom-set [-h] [-s <QMP socket path | addr:port>] <path>.<property> <value>

mdroth@illuin:~$ qom-get -h
environment variables:
    QMP_SOCKET=<path | addr:port>
usage:
    /home/mdroth/bin/qom-get [-h] [-s <QMP socket path | addr:port>] <path>.<property>

mdroth@illuin:~$ qom-list -h
environment variables:
    QMP_SOCKET=<path | addr:port>
usage:
    /home/mdroth/bin/qom-list [-h] [-s <QMP socket path | addr:port>] [<path>]