Ticket #48146 - async simple paged results issue
Description: commit 5060d11f5039efa8534a8b65392ac6e10cbd2168 introduced
a regression. Handling backend "be" should be done after checking OID
MTN_CONTROL_USE_ONE_BACKEND_EXT_OID in the request control.
https://fedorahosted.org/389/ticket/48146
Reviewed by mreynolds@redhat.com (Thank you, Mark!!)
(cherry picked from commit bd2c0d0b6a499d7f91a36e8a9feb83e4fbd3dac5)
(cherry picked from commit 0c7b38abfb4c5c02286efd5e698616534a798993)
(cherry picked from commit 2003d79eb3fbd3850c9a2590c65fbe146e96853d)