Fix MediaProvider impl scanFile to scan as MediaProvider

Some internal db ops might fail or return incorrect results if we
don't scan as MediaProvider

Also removed unused scanFileForFuse

Test: presubmit
Bug: 175810190

Change-Id: Iaba557a58afa9c8adc6c7f18490bc5651db9e581
Merged-In: Iaba557a58afa9c8adc6c7f18490bc5651db9e581
(cherry picked from commit d6431c76d9b07228475e8e4806e64b54de5cf145)
4 files changed