Update README - file injection is not required

Change-Id: I2b9bb1560ca26b50ed1f9453bc8f42b679dcd0b1
Heat is quite usable in more than Grizzly

Change-Id: Ie38a7005451477041a7805c3f757090279c10f90
Update os-*-config section of README

The old section did not consider os-collect-config.

Change-Id: I22cb7cdc0fb9482c75062d485fa0efb7c594f1bd
Merge "Update README - file injection is not required"
Merge "Heat is quite usable in more than Grizzly"
Merge "Update os-*-config section of README"