Fix ConditionUnknown after valid buckets

Because non-zero enums are evaluated to true, it is possible for pulls
to occur on bucket split even if the condition is unknown. Explicitly
check that the condition is true instead.

Bug: 155489707
Test: atest statsd_test
Change-Id: I0bc3de6e885c2200885caf01d07c793b83eca17a
2 files changed