vhost: fix error path when setting memory tables

vhost: fix error path when setting memory tables

If an error is encountered before the memory regions are
parsed, the file descriptors for these shared buffers are
leaked.

This patch fixes this by closing the message file descriptors
on error, taking care of avoiding double closing of the file
descriptors. guest_pages is also freed, even though it was not
leaked as its pointer was not overridden on subsequent function
calls.

Fixes: 8f972312b8f4 ("vhost: support vhost-user")
Cc: stable@dpdk.org
Reported-by: Xuan Ding <xuan.ding@intel.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
Reviewed-by: Xueming Li <xuemingl@nvidia.com>