installd: Invert the default for dexopt-on-cache

The growth of /system apps and total /data space are making this
device-breaking (insufficient space to dexopt everything to
/cache), pointless (/data has more than enough room to hold
the cache), and in some cases, both.
The default behavior is now the same as mainline Android's: dexopt
everything to /data. Set dalvik.vm.dexopt-data-only=0 to change
that and dexopt /system apps to /cache. If you do that, make sure
your /cache can accomodate double the size of the dex classes in
system, since in some extreme cases that has been observed during
dex2oat

Change-Id: I8c793784af1fa804ccf84b442613d1000c9b7ce4
Revert "SensorEventQueue: Allow setRate on sensor enable"

This reverts commit fd7ab408e2b3611a2083c47846757432a080bc9b.
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