Move to Mongo26 SCL
As of Pulp 2.8, an algorithm has been put into place that handles issues with packages that have the same NVRA but different checksums. This algorithm varies in run time based upon Mongo 2.4 or 2.6. The EL6 provided MongoDB is stuck at 2.4 while EL7 is at 2.6.
1. Carry and build mongo 2.6 for EL6 ourselves
2. Switch to the mongodb SCL for EL6 and El7