Update max length for access key (#247)

This caused the client to break after a recent change to prefix access
keys with "AS-". Likely this was causing the access key to be truncated.

src/forms/firstRunWizard/apikeyspage.cpp

@@ -71,7 +71,7 @@ ApiKeysPage::ApiKeysPage(QWidget *parent)
   _lblAKey->setText(tr("Access Key"));
 
   accessKeyLine = new QLineEdit(this);
-  accessKeyLine->setMaxLength(24);
+  accessKeyLine->setMaxLength(27);
   accessKeyLine->setTextMargins(3,0,3,0);
   accessKeyLine->setMaximumWidth(fontMetrics().averageCharWidth() * 27);
   registerField("host.accessKey*", accessKeyLine);