network: add missing systemd dep

Slipped by somehow.

Change-Id: I1f9273255b196b912c6bda0bc08d0320ba1807fd
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/common/recipes-phosphor/network/network.bb b/common/recipes-phosphor/network/network.bb
index 23459d9..99ea07a 100644
--- a/common/recipes-phosphor/network/network.bb
+++ b/common/recipes-phosphor/network/network.bb
@@ -9,6 +9,7 @@
 DBUS_SERVICE_${PN} += "org.openbmc.NetworkManager.service"
 SYSTEMD_SERVICE_${PN} += "network-update-dns.service"
 
+DEPENDS += "systemd"
 RDEPENDS_${PN} += "python-dbus python-pygobject python-ipy"
 
 SRC_URI += "git://github.com/openbmc/phosphor-networkd"