/etc/init.d/xendomains does not filter out backups of domU's configuration files

Ubuntu releases : from 14.04 to 16.04 at least
Latest package version with the bug : 4.5.1-0ubuntu1.3

Use case :

 After changing the domU name in /etc/xen/auto/mydomU.cfg my editor creates a backup file /etc/xen/auto/mydomU.cfg~

 Then, when rebooting, xendomains starts the domU twice : once with the old name and once with the new name but using the same virtual block devices then corrupting the filesystem on them (btrfs in my case).

 Expected behavior :

 Only the domU configured in /etc/xen/auto/mydomU.cfg should start.

 Proposed solution :

 /etc/init.d/xendomains should enforce not only domU names but extensions of files in $XENDOMAINS_AUTO

in
 do_start_auto()

I suggest changing :

  for file in $XENDOMAINS_AUTO/*; do

to

 for file in $XENDOMAINS_AUTO/*.cfg; do

And document the change (display a message when upgrading xen-utils-common).

Other consistency checks may be useful like refusing to start a domU using a VBD already in use (but this may be a needed feature of xen-hotplug).