enable using both syncMode and syncmode

lib/cmds/blockchain/blockchain.js

@@ -45,6 +45,7 @@ var Blockchain = function(options) {
     vmdebug: this.blockchainConfig.vmdebug || false,
     targetGasLimit: this.blockchainConfig.targetGasLimit || false,
     syncMode: this.blockchainConfig.syncMode,
+    syncmode: this.blockchainConfig.syncmode,
     verbosity: this.blockchainConfig.verbosity
   };
 

lib/cmds/blockchain/geth_commands.js

@@ -20,8 +20,8 @@ class GethCommands {
       cmd.push(`--datadir=${config.datadir}`);
     }
 
-    if (config.syncMode) {
-      cmd.push("--syncmode=" + config.syncMode);
+    if (config.syncMode || config.syncmode) {
+      cmd.push("--syncmode=" + (config.syncMode || config.syncmode));
     }
 
     if (config.account && config.account.password) {

test/blockchain.js

@@ -39,6 +39,7 @@ describe('embark.Blockchain', function () {
           wsRPC: true,
           targetGasLimit: false,
           syncMode: undefined,
+          syncmode: undefined,
           verbosity: undefined,
           proxy: true
         };
@@ -81,6 +82,7 @@ describe('embark.Blockchain', function () {
           wsRPC: true,
           targetGasLimit: false,
           syncMode: undefined,
+          syncmode: undefined,
           verbosity: undefined,
           proxy: true
         };