Fixed broken VoicemailContentProviderTest.

The tests were broken in two areas following recent changes
- permission READ_WRITE_OWN_VOICEMAIL was renamed to ADD_VOICEMAIL in
  the production code, but was not renamed in test.
- Two new synthetic fields DISPLAY_NAME and SIZE were added in the
  production code but the expected num fields were not updated in the
  tests.

Change-Id: I96c1997af8dadb5a95d7224b0364cf48e6244977
3 files changed