Make Keystone API's Region available

Just in case. This makes it possible to refer to it
without hardcoding the Region Name.
Merge pull request #209 from dirkmueller/release/stoney/master

Make Keystone API's Region available
add the user/pass to the keystone_settings hash

The intention is to move the code duplicated in each
cookbook (e.g. cinder, ceilometer, nova) from COOKBOOKHelper into this
central KeystoneHelper where it can be used by all of them.
refactor chef search and result processing