Make more use of RoleSpec struct

Peter Eisentraut <peter_e@gmx.net>

Commit: 2e254130d1d3f16575f2d72952ab23b4e27d035a
Author: Peter Eisentraut <peter_e@gmx.net>
Date: 2016-12-29T15:49:39Z
Releases: 10.0
Make more use of RoleSpec struct

Most code was casting this through a generic Node.  By declaring
everything as RoleSpec appropriately, we can remove a bunch of casts and
ad-hoc node type checking.

Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com>

Files