Tolerate roles in context.RequestContext
Tolerate roles in context.RequestContext

In Ia575ba803a0fb70f39146bd75d381ed19414bd23, oslo.context
added roles support in the context itself. Once that change
is released in oslo.context and the global requirements has
been updated, we should switch to passing in the roles in
the __init__ parameter. Until then we should set
self.roles *after* the constructor since the constructor
sets the roles to None when the new library gets released.

Closes-Bug: 1549317
Change-Id: Ie28a4144ccac5d6894405ba7f801617376e35c51

NaohiroTamura/ironic,openstack/ironic,bacaldwell/ironic,pshchelo/ironic,NaohiroTamura/ironic,openstack/ironic,SauloAislan/ironic,pshchelo/ironic,bacaldwell/ironic,SauloAislan/ironic,devananda/ironic