squid: fix systemd unit file location

squid.service is in tools/systemd/, not in tools/.

Fixes:

  http://autobuild.buildroot.net/results/cec/cecb968172cb00281e439566e5ae154538435a51/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/squid/squid.mk

@@ -90,7 +90,7 @@ define SQUID_INSTALL_INIT_SYSV
 endef
 
 define SQUID_INSTALL_INIT_SYSTEMD
-	$(INSTALL) -D -m 0644 $(@D)/tools/squid.service \
+	$(INSTALL) -D -m 0644 $(@D)/tools/systemd/squid.service \
 		$(TARGET_DIR)/usr/lib/systemd/system/squid.service
 	mkdir -p $(TARGET_DIR)/etc/systemd/system/multi-user.target.wants
 	ln -sf ../../../..//usr/lib/systemd/system/squid.service \