Fixed the ECFlowRuleStore to support MODIFY flow rule operations.

Change-Id: If1ee4b1d2af120535b21b0914ec30aa8930539d1
diff --git a/core/store/dist/src/main/java/org/onosproject/store/flow/impl/ECFlowRuleStore.java b/core/store/dist/src/main/java/org/onosproject/store/flow/impl/ECFlowRuleStore.java
index cd29b77..266e6fb 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/flow/impl/ECFlowRuleStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/flow/impl/ECFlowRuleStore.java
@@ -470,6 +470,7 @@
                     StoredFlowEntry entry;
                     switch (op.operator()) {
                         case ADD:
+                        case MODIFY:
                             entry = new DefaultFlowEntry(op.target());
                             // always add requested FlowRule
                             // Note: 2 equal FlowEntry may have different treatment
@@ -486,9 +487,6 @@
                                 return op;
                             }
                             break;
-                        case MODIFY:
-                            //TODO: figure this out at some point
-                            break;
                         default:
                             log.warn("Unknown flow operation operator: {}", op.operator());
                     }