Mention some packages incompatible with OpenStack
Mention some packages incompatible with OpenStack

In future, Anvil should be able to detect such problems
and automatically decide to install these packages with pip.

Change-Id: I7f570aa6e146bc10313b7870995c13be5cc55a7a

mc2014/anvil,stackforge/anvil,stackforge/anvil,mc2014/anvil