1124570 - Adds two-queue implementation for reserved resources

https://bugzilla.redhat.com/show_bug.cgi?id=1124570

This BZ implements this [design and TODO list](https://fedorahosted.org/pulp/wiki/TwoQueueReservedResourceDesign). Refer to that doc for more info on what is contained in this PR.
The test was right, and the code was wrong. TaskStatus was getting saved in two places, and the tags were different on those calls. The second call had tags set to ```[]``` which was overwriting the real tag list that was saved as part of the first call. Now the tags are preserved so they are set twice by both the first and second call so the test did not need to be modified.