Delete bridge controller API implementation,which is needed for certain use cases of ovsdb switch configuration process

Change-Id: If5f86d8b0bff95ac718556e688313e4988fdbfd6
diff --git a/protocols/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/OvsdbConstant.java b/protocols/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/OvsdbConstant.java
index cb2a31e..03321da 100644
--- a/protocols/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/OvsdbConstant.java
+++ b/protocols/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/OvsdbConstant.java
@@ -103,4 +103,7 @@
 
     /** Ovsdb port. */
     public static final int OVSDBPORT = 6640;
+
+    /** Ovsdb Bridge table, Controller column name. */
+    public static final String BRIDGE_CONTROLLER = "controller";
 }