[mako] test-sims-offline fails due to CallVolume 'Muted' property

When mako is in flight-mode, and the test case 'test-sims-offline' is run, it fails an assertion due to the CallVolume 'Muted' property being inverse from other devices ( it's 0, when it should be 1 ).

This bug was found while testing a silo containing lxc-android-config, nuntium, and ofono for the touch OTA5 milestone. Note, a newer version of network-manager ( 4ubuntu15.1.4 ) was also installed when this bug was discovered.

root@ubuntu-phablet:/usr/share/ofono/scripts/rilmodem/sim# ./test-sims-offline
F
======================================================================
FAIL: test_main (__main__.TestSimsOffline)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "./test-sims-offline", line 101, in test_main
    self.main(args)
  File "/usr/share/ofono/scripts/rilmodem/sim/simtestutil.py", line 391, in main
    self.validate_modem(modem[0])
  File "./test-sims-offline", line 98, in validate_modem
    self.validate_call_volume_properties(path)
  File "/usr/share/ofono/scripts/rilmodem/sim/simtestutil.py", line 304, in validate_call_volume_properties
    self.assertTrue(properties["Muted"] == 1)
AssertionError: False is not true

----------------------------------------------------------------------
Ran 1 test in 0.158s

FAILED (failures=1)

SystemImageInfo:

current build number: 1
device name: mako
channel: ubuntu-touch/rc/ubuntu
last update: 2015-06-27 00:49:36
version version: 1
version ubuntu: 20150611.3
version device: 20150210
version custom: 20150617