Use rpc config to run qubes.USB as root

Instead of sudo. It makes it work out of the box on a minimal template.
And also will work if sudo is not installed.

QubesOS/qubes-issues#9599

Author: marmarek

Makefile

@@ -3,6 +3,9 @@ install-vm:
 	install qubes-rpc/qubes.USBAttach $(DESTDIR)/etc/qubes-rpc
 	install qubes-rpc/qubes.USBDetach $(DESTDIR)/etc/qubes-rpc
 	install qubes-rpc/qubes.USB $(DESTDIR)/etc/qubes-rpc
+	install -d $(DESTDIR)/etc/qubes/rpc-config
+	install -T -m 0644 qubes-rpc/qubes.USB.config \
+		$(DESTDIR)/etc/qubes/rpc-config/qubes.USB
 	install -d $(DESTDIR)/usr/lib/qubes
 	install src/usb-* $(DESTDIR)/usr/lib/qubes
 	install -d $(DESTDIR)/usr/lib/udev/rules.d

qubes-rpc/qubes.USB.config

@@ -0,0 +1 @@
+force-user='root'

rpm_spec/qubes-usb-proxy.spec.in

@@ -31,6 +31,7 @@ make install-vm DESTDIR=${RPM_BUILD_ROOT}
 /etc/qubes-rpc/qubes.USB
 /etc/qubes-rpc/qubes.USBAttach
 /etc/qubes-rpc/qubes.USBDetach
+/etc/qubes/rpc-config/qubes.USB
 /etc/qubes/suspend-pre.d/usb-detach-all.sh
 /usr/lib/qubes/usb-import
 /usr/lib/qubes/usb-export