package/dhcp: create tmpfiles.d directory

dhcp.mk tries to create dhcp.conf in a non-existant directory.

Fixes:
http://autobuild.buildroot.net/results/40e/40e48f74b586ce380766cf31473932e43090671e

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Tested-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/dhcp/dhcp.mk

@@ -102,6 +102,7 @@ define DHCP_INSTALL_INIT_SYSTEMD
 	ln -sf ../../../../usr/lib/systemd/system/dhcpd.service \
 		$(TARGET_DIR)/etc/systemd/system/multi-user.target.wants/dhcpd.service
 
+	mkdir -p $(TARGET_DIR)/usr/lib/tmpfiles.d
 	echo "d /var/lib/dhcp 0755 - - - -" > \
 		$(TARGET_DIR)/usr/lib/tmpfiles.d/dhcpd.conf
 	echo "f /var/lib/dhcp/dhcpd.leases - - - - -" >> \