apply intern (#52)

* apply intern

* care nil case

* re-write

Author: KazuCocoa

CHANGELOG.md

@@ -6,6 +6,7 @@ All notable changes to this project will be documented in this file.
 - Add `window_rect`
 
 ### Bug fixes
+- Make `@driver.automation_name` symbol when someone define the `automationName` with the server argument.
 
 ### Deprecations
 

lib/appium_lib_core/driver.rb

@@ -458,7 +458,9 @@ def set_automation_name
       # @private
       def set_automation_name_if_nil
         return unless @automation_name.nil?
-        @automation_name = @driver.capabilities['automationName']
+        @automation_name = if @driver.capabilities['automationName']
+                             @driver.capabilities['automationName'].intern
+                           end
       end
 
       # @private