Fix format error in claims.

I have now seen two bug reports today about log message formatting
in the claims code. I'm not 100% sure what's going on here, but
I've removed the use of locals() in the hope it makes it clearer.
I've also moved to treating limits as floats because I think it
makes the messages clearer, but it is not a functional change.

Resolves bug 1175923.

Change-Id: I8b7b31f2637d1ab41d0fb2f274545181f9fddd9d
Merge "Fix format error in claims."