Publish fabric.p4 constants with fabric-api artifact

For consumption by third-party apps who wish to operate directly on
fabric.p4 tables and other entities.

Change-Id: Iec8a18c3355767d92e2ca8595017632760c0cbd1
diff --git a/pipelines/fabric/impl/src/test/java/org/onosproject/pipelines/fabric/impl/behaviour/FabricInterpreterTest.java b/pipelines/fabric/impl/src/test/java/org/onosproject/pipelines/fabric/impl/behaviour/FabricInterpreterTest.java
index a0e6194..7ee9c88 100644
--- a/pipelines/fabric/impl/src/test/java/org/onosproject/pipelines/fabric/impl/behaviour/FabricInterpreterTest.java
+++ b/pipelines/fabric/impl/src/test/java/org/onosproject/pipelines/fabric/impl/behaviour/FabricInterpreterTest.java
@@ -28,6 +28,7 @@
 import org.onosproject.net.flow.TrafficTreatment;
 import org.onosproject.net.pi.runtime.PiAction;
 import org.onosproject.net.pi.runtime.PiActionParam;
+import org.onosproject.pipelines.fabric.FabricConstants;
 
 import static org.easymock.EasyMock.createNiceMock;
 import static org.easymock.EasyMock.expect;