Change the service dependency to mandatory

Change-Id: I81f42c9a72231ffd9dd0e0045b46225a6ccf819f
diff --git a/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/xconnect/impl/XconnectManager.java b/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/xconnect/impl/XconnectManager.java
index 9947bb8..b5d02d2 100644
--- a/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/xconnect/impl/XconnectManager.java
+++ b/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/xconnect/impl/XconnectManager.java
@@ -126,7 +126,7 @@
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     public MastershipService mastershipService;
 
-    @Reference(cardinality = ReferenceCardinality.OPTIONAL_UNARY)
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     public SegmentRoutingService srService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)