The attached patch adds a variable at the top of lxc-debian to change the SUITE.
Currently tested suites are lenny, squeeze, sid.

Also, the patch uses the dhcp3-client package instead of dhcp-client which is
deprecated in lenny and removed in squeeze.

Patch initialy from Mathieu Parent.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>