explicitly detach loop device on umount and silent losetup error

Umount detaches the loop device automatically, but let's make it
explicit to be sure. Additionally losetup gives:

losetup: /dev/loop0: detach failed: No such device or address

This is kind of expected, let's silent the error message.

Signed-off-by: Christian Hesse <mail@eworm.de>

1 files changed, 1 insertions, 1 deletions

diff --git a/hooks/archiso_loop_mnt b/hooks/archiso_loop_mnt
index a02cfac..46338e5 100644
--- a/hooks/archiso_loop_mnt
+++ b/hooks/archiso_loop_mnt
@@ -26,7 +26,7 @@ archiso_loop_mount_handler () {
     archiso_mount_handler ${newroot}
 
     if [[ "${copytoram}" == "y" ]]; then
-        losetup -d ${_dev_loop}
+        losetup -d ${_dev_loop} 2>/dev/null
         umount /run/archiso/img_dev
     fi
 }