bitkeeper revision 1.1513.1.1 (42925a6aSZSwfyaVsNzV4psPmpZwZg)

bitkeeper revision 1.1513.1.1 (42925a6aSZSwfyaVsNzV4psPmpZwZg)

Execute xc_linux_restore in a seperate process so that it can't
crash xend.  Also handle errors passed from xc_linux_restore and
log info messages from xc_linux_restore.
XendDomain.py:
  Popen xc_restore instead of calling xc_linux_restore directly.
xc.c:
  Add pyxc_handle exporting the file descriptor to the control interface.
  Remove xc_linux_restore -- replaced by popen of xc_restore directly
  from python.
xc_linux_restore.c:
  Enable debug output.
xpopen.py:
  Add xpopen functionality:
  Optionally exclude a list of file descriptors from being closed, allowing
  access to those file descriptors from the command.
  Remove unused parts.
xpopen.py, Makefile, xc_restore.c:
  new file
Makefile:
  Add xcutils subdir.
ignore:
  Add tools/xcutils/xc_restore.
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>