message: API: Fix 'should export admin data' getRandomStudent
  While this now uses getRandomAdmin instead of getRandomStudent,
  I am not sure about the Travis CI test failure mentioned in:
  (Local test ran fine independent of the change in this commit.)
diff: @@ -208,7 +208,7 @@ describe('Export', async () => {
  it('should export admin data', async () => {
  - const admin = await FixtureUtils.getRandomStudent();
  + const admin = await FixtureUtils.getRandomAdmin();
  const result = await chai.request(app)
  .get(`${BASE_URL}/user`)
  