"isMediaDatabaseName" API has to return true only if a parameter is database file path.

But it check only prefix with 'external-'.
Media provider uses Write Ahead Logging that makes wal and shm files.
In case of wal and shm files, the API can also return true.
So additionally, the API has to confirm that the file path has '.db' extension.

Signed-off-by : kwangjung kim <kwangjung.kim@lge.com>

Change-Id: Ibc394ab5dac169b126bce58d9416d2196b1afe61