Filters and/or Servlets cannot be added to context [/openmrs] as the context has been initialised

@dkayiwa and @ibacher could you help advise whether either or both of TRUNK-4673 and TRUNK-6169 can make it into Platform 2.7?

As far as we can tell, we’re are definitely facing an issue at first startup when two modules like Data Filter and OAuth 2 Login are used together.

Cc @achachiez @corneliouzbett @ruhanga