lorax-templates-qubes: provide dummy /proc/modules for dracut

Updated dracut don't like not having /proc/modules - modules
installation routines fails then, producing initramfs without kernel
modules at all. Empty /proc/modules is enough to avoid this.

QubesOS/qubes-issues#2574

lorax-templates-qubes/templates/efi.tmpl

@@ -49,10 +49,12 @@ install boot/efi/EFI/*/fonts/unicode.pf2 ${EFIBOOTDIR}/fonts/
     %if include_kernel:
         copy ${KERNELDIR}/vmlinuz ${EFIBOOTDIR}
         runcmd chroot ${inroot} mkdir -p /boot/efi/EFI/qubes
+        runcmd chroot ${inroot} touch /proc/modules
         runcmd chroot ${inroot} dracut --nomdadmconf --nolvmconf --nofscks --no-early-microcode --no-hostonly --xz --install '/.buildstamp' \
           --add 'anaconda pollcdrom dmsquash-live' \
           --omit="${extra_dracut_modules}" --omit-drivers="${scsi_modules}" --omit-drivers="${extra_modules}" \
           /boot/efi/EFI/qubes/initrd-small.img ${kver}
+        runcmd chroot ${inroot} rm -f /proc/modules
         install boot/efi/EFI/qubes/initrd-small.img ${EFIBOOTDIR}/initrd.img
     %endif
     install ${configdir}/grub2-efi.cfg ${eficonf}