test: adapt RPC test for restricted socket permissions

The service socket now defaults to 0600 (owner-only). Since the
test runs the setuid criu binary as a non-root user (uid 1000),
the socket ends up owned by root. Chown the socket to the test
user after service startup so it can connect, mirroring what an
administrator would do in production.

Assisted-by: Claude Code (claude-opus-4-6):claude-opus-4-6@default

Generated with Claude Code (https://claude.ai/code)

Signed-off-by: Adrian Reber <areber@redhat.com>

test/others/rpc/Makefile

@@ -32,6 +32,8 @@ run: all
 		-d --pidfile pidfile -o service.log --status-fd 200; \
 		$(PYTHON) read.py build/status"
 	rm -f build/status
+	@# Socket defaults to 0600; transfer ownership to the test user.
+	chown 1000:1000 build/criu_service.socket
 	chmod a+rw build/pidfile
 	sudo -g '#1000' -u '#1000' ./run.sh
 	sudo -g '#1000' -u '#1000' ./version.py