Fix parameter type in vhost migration log path

Fix parameter type in vhost migration log path

The ‘enable’ parameter to the vhost_migration_log() function is given as
an int, but "true"/"false" values are passed in wherever it is invoked.
Inside the function itself it is only ever compared with bool values.
Therefore the parameter value itself should be changed to bool.

Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <CAFubqFtqNZw=Y-ar3N=3zTQi6LkKg_G-7W7OOHHbE7Y1fV7HAQ@mail.gmail.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>