Flow id test was in the wrong package

Change-Id: Id2d155500fe9f25051f82fe550ca41ac64d671ef
diff --git a/core/net/src/test/java/org/onlab/onos/net/flow/FlowIdTest.java b/core/api/src/test/java/org/onlab/onos/net/flow/FlowIdTest.java
similarity index 100%
rename from core/net/src/test/java/org/onlab/onos/net/flow/FlowIdTest.java
rename to core/api/src/test/java/org/onlab/onos/net/flow/FlowIdTest.java