Fixed VoicemailStatusHelperlTestImpl test.

The current implementation of VoicemailStatusHelperImplTest assumed a
clean voicemail_status table. This may not be true if the database
previously had non-test entries populated.

This change restricts the scope of db query to only the test packages.

Change-Id: Ica61ed53fc43e5fa427afcd3427c6054fcc742da
1 file changed