[rb] unguard specs now working in Firefox 56

mozilla/geckodriver#463
mozilla/geckodriver#660

Author: lmtierney

rb/spec/integration/selenium/webdriver/action_builder_spec.rb

@@ -150,7 +150,7 @@ module WebDriver
           expect(element.attribute(:value)).to eq('DoubleClicked')
         end
 
-        it 'context clicks an element', except: {browser: :firefox} do
+        it 'context clicks an element' do
           driver.navigate.to url_for('javascriptPage.html')
           element = driver.find_element(id: 'doubleClickField')
 

rb/spec/integration/selenium/webdriver/options_spec.rb

@@ -86,7 +86,7 @@ module WebDriver
           expect(driver.manage.all_cookies).to be_empty
         end
 
-        it 'should use DateTime for expires', except: {browser: %i[firefox safari]} do
+        it 'should use DateTime for expires', except: {browser: :safari} do
           driver.navigate.to url_for('xhtmlTest.html')
 
           expected = DateTime.new(2039)