Use the varialbe to export right keystone api version

Change-Id: I1e8ea2b7173c549065ed1f08814eb4b4bb2f05cd
Fixes: Bug #1217783
Move Heat to a single heat.conf

the old config files that are no longer needed (but still supported):
heat-engine.conf, heat-api.conf, heat-api-cfn.conf, heat-api-cw.conf

Change-Id: I7ba0566325539bf7215bcb606843a90b5e3e4a98
Merge "Use the varialbe to export right keystone api version"
Merge "Move Heat to a single heat.conf"