Tune down node_locked_retry_{attempts,interval} config for tests

Tune down the node_locked_retry_interval and
node_locked_retry_attempts config options for tests. The commit
428c24767575419d5b472b52f2b622588a3a7253 introduced a new retry mechanism
for the NodeLocked exception but the config options weren't resetted for
the tests so the tests verifying that exception were wasting time sleeping.

Closes-Bug: #1348586
Change-Id: Ia516ede357b00ebb19d10f2f603a3e766478c1b3
Merge "Tune down node_locked_retry_{attempts,interval} config for tests"