ignore stderr since geth outputs normal logs to it

Author: iurimatias

lib/cmds/blockchain/blockchain.js

@@ -194,7 +194,7 @@ Blockchain.prototype.checkPathLength = function() {
 Blockchain.prototype.isClientInstalled = function(callback) {
   let versionCmd = this.client.determineVersionCommand();
   this.runCommand(versionCmd, {}, (err, stdout, stderr) => {
-    if (err || stderr || !stdout || stdout.indexOf("not found") >= 0) {
+    if (err || !stdout || stdout.indexOf("not found") >= 0) {
       return callback('Geth not found');
     }
     callback();