Renamed the iBFT NEW_CHAIN_HEAD_HEADER event type to NEW_CHAIN_HEAD (#114)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

consensus/ibft/src/main/java/tech/pegasys/pantheon/consensus/ibft/IbftEvents.java

@@ -22,7 +22,7 @@ public class IbftEvents {
 
   public enum Type {
     ROUND_EXPIRY,
-    NEW_CHAIN_HEAD_HEADER,
+    NEW_CHAIN_HEAD,
     BLOCK_TIMER_EXPIRY
   }
 }

consensus/ibft/src/main/java/tech/pegasys/pantheon/consensus/ibft/ibftevent/NewChainHead.java

@@ -35,7 +35,7 @@ public final class NewChainHead implements IbftEvent {
 
   @Override
   public Type getType() {
-    return Type.NEW_CHAIN_HEAD_HEADER;
+    return Type.NEW_CHAIN_HEAD;
   }
 
   @Override