fix test and add assertion

Author: bleskes

server/src/main/java/org/elasticsearch/index/shard/IndexShard.java

@@ -525,6 +525,11 @@ public void onFailure(Exception e) {
             }
             // set this last, once we finished updating all internal state.
             this.shardRouting = newRouting;
+
+            assert this.shardRouting.primary() == false ||
+                this.shardRouting.started() == false || // note that we use started and not active to avoid relocating shards
+                this.replicationTracker.isPrimaryMode()
+                : "an started primary must be in primary mode " + this.shardRouting;
             shardStateUpdated.countDown();
         }
         if (currentRouting != null && currentRouting.active() == false && newRouting.active()) {

server/src/test/java/org/elasticsearch/indices/cluster/AbstractIndicesClusterStateServiceTestCase.java

@@ -362,7 +362,8 @@ public void updateShardState(ShardRouting shardRouting,
             } else if (shardRouting.primary()) {
                 // note: it's ok for a replica in post recovery to be started and promoted at once
                 // this can happen when the primary failed after we sent the start shard message
-                assertTrue("a replica can only be promoted when started", shardRouting.started());
+                assertTrue("a replica can only be promoted when active. current: " + this.shardRouting + " new: " + shardRouting,
+                    shardRouting.active());
             }
             this.shardRouting = shardRouting;
             if (shardRouting.primary()) {