packaging: hplip udev rules conflict with foo2zjs

foo2zjs and hplip are both printer drivers for HP LaserJet 1018 (and others).
Both install their own udev rules. Those rules are conflicting as both try to upload the firmware to the printer:

From /lib/udev/rules.d/85-hplj10xx.rules (foo2zjs):
#Own udev rule for HP Laserjet 1018
KERNEL=="lp*", SUBSYSTEMS=="usb", ATTRS{idVendor}=="03f0", ATTRS{product}=="HP LaserJet 1018", SYMLINK+="hplj1018-%n", RUN+="/usr/sbin/hplj1018"

From /etc/udev/rules.d/86-
# hp_laserjet_1018
SUBSYSTEM=="usb_device", SYSFS{idVendor}=="03f0", SYSFS{idProduct}=="4117", PROGRAM="/bin/sh -c 'X=%k; X=$${X#usbdev}; B=$${X%%%%.*}; D=$${X#*.}; logger -p user.info loading hp_laserjet_1018 firmware $$B $$D; printf %%03i:%%03i $$B $$D'", RUN+="/bin/sh -c '/usr/bin/hp-firmware -y3 -s%c &'"

As those rules are not declared in the same way they are probably both executed (sorry I don't know much udev) and the result is that the firmware upload fails. When I uninstalled foo2zjs, the printer worked.

So I think that foo2zjs should be declared as incompatible with hplip in the hplip .deb.