Migrations with xl migrate --debug will fail because debugging
information from the receiving process is written to the stdout
channel. This channel is also used for status messages so the
migration will fail as the sending process receives an unexpected
message. This patch moves the debugging information to the stderr
channel.
Signed-off-by: Michael Young <m.a.young@durham.ac.uk> Acked-by: Ian Campbell <ian.campbell@citrix.com>