sensorservice: Fix init sequence for pre-1.1 API sensor HALs

The sensors API introduced a new flush() method that older binaries
won't have. For those, replace the firstFlush invocation with a
setDelay call since a lot of implementations interpreted that as
the initialization step.

Change-Id: I26ce923fe385751fed7d1c483a53c074249f0620
Merge remote-tracking branch 'cm/cm-11.0' into cm-11.0