Update mediawiki_selenium Ruby gem to the latest version

Bug: 117976
Change-Id: I567880afcf7dc5d70e6d4edef1db16d7923ae31c

tests/browser/features/step_definitions/accept_language_steps.rb

@@ -1,6 +1,6 @@
 Given(/^that my browser's accept language is (.+)$/) do |language|
-  @browser = browser(test_name(@scenario), {language: language})
-  $session_id = @browser.driver.instance_variable_get(:@bridge).session_id
+  browser = browser(test_name(@scenario), {language: language})
+  $session_id = browser.driver.instance_variable_get(:@bridge).session_id
 end
 
 When(/^I am at the preferences page$/) do

tests/browser/features/step_definitions/ime_steps.rb

@@ -3,7 +3,7 @@
 Given(/^I am on a wiki in Kotava language$/) do
   step "I am at the main page"
   # Fake a Kotava Wiki
-  @browser.execute_script( "mw.config.set( 'wgContentLanguage', 'avk' )" )
+  browser.execute_script( "mw.config.set( 'wgContentLanguage', 'avk' )" )
 end
 
 When(/^I click on an input box$/) do
@@ -55,7 +55,7 @@ When(/^I press Control-M$/) do
 end
 
 When(/^I reload the page$/) do
-  @browser.refresh
+  browser.refresh
 end
 
 Then(/^in it there must be an element with Malayalam text$/) do

tests/browser/features/step_definitions/panel_steps.rb

@@ -1,5 +1,5 @@
 Then(/^I see "(.*?)" as the name of the content language$/) do |text|
-	@browser.span(:text => "#{text}").should be_visible
+	browser.span(:text => "#{text}").should be_visible
 end
 
 When(/^I open the Universal Language Selector$/) do