serial Wacom devices not detected in vivid/15.04

After installing Ubuntu Vivid/15.04 on my Thinkpad x200 tablet, no serial Wacom devices were detected at boot. Screen did not respond to stylus and Wacom settings reported no tablet detected.

Workaround: as in comment #8 in Utopic bug #<a href="https://bugs.launchpad.net/ubuntu/+source/xf86-input-wacom/+bug/1392887">1392887</a>, replacing the directory /lib/udev/rules.d/69-wacom.rules with the *file /lib/udev/rules.d/69-wacom.rules/wacom.rules, renamed to "69-wacom.rules" restores Wacom functionality. However, the laptop now boots up into portrait mode. Replacing /lib/udev/rules.d/69-wacom.rules/wacom.rules with the Utopic/14.04 version does not appear to fix the problem.