docker: Don't mount ccache db if NOUSER=1

With NOUSER=1 the container runs code as root, which may create
privileged files that will not be be accssible next time. Skip ccache
dir mount in this case.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20170925075458.18047-1-famz@redhat.com>
Acked-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

tests/docker/Makefile.include

@@ -143,9 +143,11 @@ docker-run: docker-qemu-src
 			-e EXTRA_CONFIGURE_OPTS="$(EXTRA_CONFIGURE_OPTS)" \
 			-e V=$V -e J=$J -e DEBUG=$(DEBUG)		\
 			-e SHOW_ENV=$(SHOW_ENV) 			\
-			-e CCACHE_DIR=/var/tmp/ccache 			\
+			$(if $(NOUSER),,				\
+				-e CCACHE_DIR=/var/tmp/ccache 		\
+				-v $(DOCKER_CCACHE_DIR):/var/tmp/ccache:z \
+			)						\
 			-v $$(readlink -e $(DOCKER_SRC_COPY)):/var/tmp/qemu:z$(COMMA)ro \
-			-v $(DOCKER_CCACHE_DIR):/var/tmp/ccache:z 	\
 			$(IMAGE) 					\
 			/var/tmp/qemu/run 				\
 			$(TEST), "  RUN $(TEST) in ${IMAGE}")