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.
We also don't want any kind of call to flush() to happen when it
isn't there, since it'll either hit a random OEM extension or
a memory address we really don't want to execute.

Change-Id: I26ce923fe385751fed7d1c483a53c074249f0620
Merge branch 'kk4.4' of https://github.com/SlimRoms/frameworks_native into kk4.4

Conflicts:
	services/sensorservice/SensorService.cpp

Change-Id: I937fcc0ddb2b0c0746eda70db48c2bb16d2c825c