Close the provider DB file when done with it.

The mobile_provider_open_db function opens the provider DB file,
reads the whole thing in, and parses it. It should have then been
closing the file, but wasn't. Now it does.

BUG=none
TEST=unit tests still run

Change-Id: I2623be7a4a0df913ffe39dac9259d6f13aaaea12
1 file changed