Make test suite output less verbose

Make test suite output less verbose

Only print out '.' for each test case, full test output can be
re-enabled with VIR_TEST_VERBOSE=1, or VIR_TEST_DEBUG=XXXX

Sample output now looks like

  TEST: statstest
        ........................................ 40
        ...................................      75  OK
  PASS: statstest
  TEST: qparamtest
        ................................         32  OK
  PASS: qparamtest
  TEST:
        ............                             12  OK