Process to update the demo server

@taremwatadeo since 2.5 is already released, when you did run the release again, you ended up by releasing reference application version 2.6, which should not be, and hence these failures: https://ci.openmrs.org/browse/RA-RA-2353. So i have deleted the 2.6 tag, which was a result of this, and changed from 2.7-SNAPSHOT back to 2.6-SNAPSHOT at https://github.com/openmrs/openmrs-distro-referenceapplication/commit/f7bbdad023a8230bd58974769a6dc7ef661c26ac