[mer-hybris] Drop android/ header prefix

See libhybris commit 94a3871bf01ff2558aa9417badf14e45c9bbeb9e
[hybrisadaptor] Return invalid handle if sensor doesn't exist

The value 0 might be a valid handle (to the first sensor). Return -1
instead to make an invalid handle that doesn't have side effects.
Merge pull request #28 from thp/no-sensor-handle

Various fixes for mer-hybris