Install systemd services with autotools

Change-Id: Ia1a4fb62dee35737ece1f3501f352501eba2449e
diff --git a/debian/osmo-trx-usrp1.install b/debian/osmo-trx-usrp1.install
index c7e54b1..112a149 100644
--- a/debian/osmo-trx-usrp1.install
+++ b/debian/osmo-trx-usrp1.install
@@ -1,3 +1,4 @@
+lib/systemd/system/osmo-trx-usrp1.service
 /usr/bin/osmo-trx-usrp1
 /usr/share/usrp/rev2/std_inband.rbf
 /usr/share/usrp/rev4/std_inband.rbf