MDL-40517 deprecatedlib: remove functions
MDL-40517 deprecatedlib: remove functions

* Removed functions which were throwing fatal errors
* Fixup navmenu comment, as it hasn't been throwing a fatal error, it
  shouldn't be removed as part of this issue yet. (Although if you are
  still using this function, you are crazy and should thank me ;-)).

dilawar/moodle