Fixed "uninitialized constant" error message

More of the error message:

$ cucumber -d -v features/
Code:
  * features/support/modules/interlanguage_module.rb
uninitialized constant InterlanguagePageModule::PageObject (NameError)
(…)/browsertests/features/support/modules/interlanguage_module.rb:2:in
`<module:InterlanguagePageModule>'
(…)

Change-Id: Idb9f726e22865811d3e7a770ff277e7b607b48dc