[PAN-2267] Update CLI options in mismatched genesis file message

ethereum/core/src/main/java/tech/pegasys/pantheon/ethereum/chain/DefaultMutableBlockchain.java

@@ -363,7 +363,7 @@ protected void setGenesis(final Block genesisBlock) {
       if (!genesisHash.get().equals(genesisBlock.getHash())) {
         throw new InvalidConfigurationException(
             "Supplied genesis block does not match stored chain data.\n"
-                + "Please specify a different data directory with --datadir or specify the original genesis file with --genesis.");
+                + "Please specify a different data directory with --data-path or specify the original genesis file with --genesis-file.");
       }
     }
   }

ethereum/core/src/test/java/tech/pegasys/pantheon/ethereum/chain/GenesisBlockMismatchTest.java

@@ -103,6 +103,6 @@ public void suppliedGenesisBlockMismatchStoredChainDataException() {
         .isThrownBy(() -> blockchain00.setGenesis(genesisBlock01))
         .withMessageContaining(
             "Supplied genesis block does not match stored chain data.\n"
-                + "Please specify a different data directory with --datadir or specify the original genesis file with --genesis.");
+                + "Please specify a different data directory with --data-path or specify the original genesis file with --genesis-file.");
   }
 }

pantheon/src/test/java/tech/pegasys/pantheon/cli/PantheonCommandTest.java

@@ -544,8 +544,8 @@ public void dataDirDisabledUnderDocker() {
 
     final Path path = Paths.get(".");
 
-    parseCommand("--datadir", path.toString());
-    assertThat(commandErrorOutput.toString()).startsWith("Unknown options: --datadir, .");
+    parseCommand("--data-path", path.toString());
+    assertThat(commandErrorOutput.toString()).startsWith("Unknown options: --data-path, .");
     assertThat(commandOutput.toString()).isEmpty();
   }