Support Constantinople when using Clique. (#247)

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

consensus/clique/src/main/java/tech/pegasys/pantheon/consensus/clique/CliqueProtocolSchedule.java

@@ -60,6 +60,10 @@ public class CliqueProtocolSchedule extends MutableProtocolSchedule<CliqueContex
     config
         .getByzantiumBlockNumber()
         .ifPresent(blockNumber -> protocolSchedule.putMilestone(blockNumber, specs.byzantium()));
+    config
+        .getConstantinopleBlockNumber()
+        .ifPresent(
+            blockNumber -> protocolSchedule.putMilestone(blockNumber, specs.constantinople()));
 
     return protocolSchedule;
   }

consensus/clique/src/main/java/tech/pegasys/pantheon/consensus/clique/CliqueProtocolSpecs.java

@@ -66,6 +66,10 @@ public class CliqueProtocolSpecs {
     return applyCliqueSpecificModifications(MainnetProtocolSpecs.byzantiumDefinition(chainId));
   }
 
+  public ProtocolSpec<CliqueContext> constantinople() {
+    return applyCliqueSpecificModifications(MainnetProtocolSpecs.constantinopleDefinition(chainId));
+  }
+
   private ProtocolSpec<CliqueContext> applyCliqueSpecificModifications(
       final ProtocolSpecBuilder<Void> specBuilder) {
     final EpochManager epochManager = new EpochManager(epochLength);

ethereum/core/src/main/java/tech/pegasys/pantheon/ethereum/mainnet/MainnetProtocolSpecs.java

@@ -263,13 +263,16 @@ public abstract class MainnetProtocolSpecs {
    */
   public static ProtocolSpec<Void> constantinople(
       final int chainId, final ProtocolSchedule<Void> protocolSchedule) {
+    return constantinopleDefinition(chainId).build(protocolSchedule);
+  }
+
+  public static ProtocolSpecBuilder<Void> constantinopleDefinition(final int chainId) {
     return byzantiumDefinition(chainId)
         .difficultyCalculator(MainnetDifficultyCalculators.CONSTANTINOPLE)
         .gasCalculator(ConstantinopleGasCalculator::new)
         .evmBuilder(MainnetEvmRegistries::constantinople)
         .blockReward(CONSTANTINOPLE_BLOCK_REWARD)
-        .name("Constantinople")
-        .build(protocolSchedule);
+        .name("Constantinople");
   }
 
   private static TransactionReceipt frontierTransactionReceiptFactory(