state/apiserver: fix test for Go 1.3
Merge pull request #442 from davecheney/167-fix-state-apiserver-for-g1.3

state/apiserver: fix test for Go 1.3

Go 1.3 has redefined the suffix when printing microsecond `time.Duration` values from _u_ to _µ_. 

Adjust the test to accommodate both the Go 1.2 and Go 1.3 behaviour.