Fix a few leaks

        * qemud/qemud.c: qemudCleanup(): free the socket
        structures

        * qemud/conf.c: fix various leaks in the xml parsing

        * qemud/iptables.c: fix a typo causing a leak

        * qemud/conf.c, qemud/qemud.c: only create config dirs
        when actually trying to write out config.

        * qemud/qemud.c: clean up qemudInitialize() and qemudListen()
        so as to coalesce the two "system vs. user" code paths and
        fix up some problems noticed by dan.

        * qemud/qemud.c: don't shutdown guest and networks on
        SIGHUP

        * qemud/qemud.c: handle SIGQUIT.

        * qemud/qemud.c, qemud/dispatch.c, qemud/internal.h
        qemud/conf.c, qemud/driver.c, configure.in: add a
        qemudLog() function which uses syslog() if we're in daemon
        mode, doesn't output INFO/DEBUG messages unless the
        verbose flag is set and doesn't output DEBUG messages
        unless compiled with --enable-debug. Also, make a first
        pass through fatal errors and add error messages for them.

        * qemud/internal.h, qemud/qemud.c: improve signal handling
        and handle SIGHUP by shutting down all guests and networks
        and re-loading configs, and handle SIGINT and SIGTERM
        by shutting down cleanly.

	* qemud/qemud.c, qemud/bridge.c, qemud/iptables.c: fix
	our FD_CLOEXEC usage so that all fds which should be
	closed on exec are marked as such and that we leave
	exec() to do the actual closing.

        * qemud/qemud.c: fix qemudEnableIpForwarding() to not leak
        an fd if writing to /proc/sys/net/ipv4/ip_forward fails.

	* qemud/conf.[ch], qemud/dispatch.c, qemud/internal.h,
	  qemud/qemud.c, qemud/driver.c: allow re-defining network
	configs; basically copying dan's patch for domains.

        * qemud/iptables.[ch]: add code for managing iptables
        rules.

        * qemud/Makefile.am: add iptables.[ch].

        * qemud/qemud.c: add and remove iptables rules as
        appropriate.

        * qemud/conf.c: when starting a guess, add a rule
        allowing it to forward packets across the networks
        bridge.

        * qemud/internal.h: add iptables context ptr

        * configure.in: add --with-iptables-dir and
        --with-iptables-prefix to allow us to put our rules
        in a chain with the given prefix and save the rules
        in files in the given dir so as to integrate with
        the proposed "service iptables restart" solution
        in:

           https://bugzilla.redhat.com/227011

        * qemud/conf.c: add support for connecting a qemu
        guest to a bridge using a tap device in order to
        connect it to a virtual network.

        * qemud/internal.h: add <interface type="network">
        config and track tapfds so as to not close them
        on exec.

        * qemud/qemud.c: don't close tapfds on exec and
        disconnect the iface when the guest shuts down.

        * qemud/conf.c, qemud/internal.h: add dhcp config

        * qemud/qemud.c: start dnsmasq to provide dns/dhcp
        for virtual networks.

        * configure.in: add --disable-bridge-params, check
        for libsysfs and various kernel headers

        * bridge.[ch]: add code for managing bridges

        * qemud/Makefile.am: add bridge.[ch] and link against
        libsysfs if enabled.

        * qemud/conf.c: add support for bridge config.

        * qemud/internal.h: add various bridging bits

        * qemud/qemud.c: implement qemudStartNetworkDaemon()
        and qemudShutdownNetworkDaemon().

        * qemud/conf.[ch]: implement parsing and saving network
        configs.

        * qemud/driver.c: flesh out the stubs

        * qemud/internal.h: add networks list etc. to
        struct qemud_server

        * qemud/qemud.c: add qemudStartNetworkDaemon() and
        qemudShutdownNetworkDaemon() stubs.

        * qemud/qemud.c: Re-factor out qemudExec() so that it can
        be used to launch dnsmasq.

        * qemud/conf.c: don't return argc from qemudBuildCommandLine()
        as exec() doesn't need it.

        * qemud/conf.c, qemud/dispatch.c, qemud/driver.c,
          qemud/qemud.c: include autoconf's config.h

        * conf.[ch]: rename from config.[ch] so we can use
        autoconf's config.h

        * Makefile.am: update

        * driver.c, qemud.c: upd.