Use "nowatch" udev rule for known inappropriate devices.

Use "nowatch" udev rule for known inappropriate devices.

For now, this is just a precaution. Normally, all the other (non-dm) rules
should check DM_UDEV_DISABLE_OTHER_RULES_FLAG and therefore avoid setting
any inotify watches as well. But let's make sure.

Support for final assignment of the "nowatch" rule (the use of ":=") will
appear in next udev release, v160. This should also work in previous udev
versions but the setting won't be sealed so any further OPTIONS="watch" will
always prevail there.

We may want to add more specific "nowatch" rules later if needed.