Add pbr to projects.txt

For automated requirements updates.

Change-Id: I4d10b180e5c067729db4a89e1b9add454068f5b0
Use OS's pypi mirror for Marconi

Marconi doesn't have any fancy dependency, let it use OpenStack's pypi
mirror.

Change-Id: Ieddac358c55791f4406cbf1416cd12d7df1c2b4e
Oslo program has adopted cliff, pycadf, stevedore, and taskflow

Gate the projects above using the internal pypi mirror as these
are official Oslo projects now

Change-Id: I2e8d8ee808750859857774b7302df16b0e34bed3
Merge "Oslo program has adopted cliff, pycadf, stevedore, and taskflow"
Merge "Use OS's pypi mirror for Marconi"
Merge "Add pbr to projects.txt"