Remove usage of locals() for formatting from nova.scheduler.*

Using of locals() for formatting string is a nasty thing because:
1) It is not so clear as using explicit dicts
2) It could produce hidden errors during refactoring
3) Changing name of variable causes change in message
4) Creating a lot of unused variables

fixes bug #1171936

Change-Id: I7639631846a9145c3a18f2a704b71184ec781f45
Merge "Remove usage of locals() for formatting from nova.scheduler.*"