rb - update expand_path for local Firefox

Author: titusfortner

rb/lib/selenium/webdriver/firefox/binary.rb

@@ -170,8 +170,8 @@ def windows_path
 
           def macosx_path
             path = "/Applications/Firefox.app/Contents/MacOS/firefox-bin"
-            path = "~/Applications/Firefox.app/Contents/MacOS/firefox-bin" unless File.exist?(File.expand_path(path))
-            path = Platform.find_binary("firefox-bin") unless File.exist?(File.expand_path?(path))
+            path = File.expand_path("~/Applications/Firefox.app/Contents/MacOS/firefox-bin") unless File.exist?(path)
+            path = Platform.find_binary("firefox-bin") unless File.exist?(path)
 
             path
           end