* src/qemu_conf.c, src/qemu_conf.h: Use -vga or -std-vga
when starting guests if video card is present
* tests/qemuhelptest.c: Change to use constants instead
of hardcoded hex numbers, and add VGA support
* tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl-fullscreen.xml,
tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl.args,
tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl.xml,
tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-sasl.args,
tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-sasl.xml,
tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-tls.xml,
tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc.xml,
tests/qemuxml2argvdata/qemuxml2argv-input-xen.xml: Add <video>
element for testing graphics adapter
* tests/qemuxml2argvtest.c: Add QEMUD_CMD_FLAG_VGA flag
* tests/qemuxml2xmltest.c: Add missing graphics-vnc-sasl/tls tests
virExec will write out the pid of the daemonized process only. Use this
in the QEMU driver, rather than QEMU's pidfile, so we can catch errors we
might miss if the emulator bails early.
