qubes/ext/gui: adjust shm.id path
qubes/ext/gui: adjust shm.id path

It's moved to /var/run/qubes and now is built based on $DISPLAY.

marmarek/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,woju/qubes-core-admin,woju/qubes-core-admin,QubesOS/qubes-core-admin,QubesOS/qubes-core-admin,marmarek/qubes-core-admin,woju/qubes-core-admin,woju/qubes-core-admin