Added test_settings_passcode.py for #477
Disable passcode in cleanUp(). #477
Modified the _passcode_enable_locator.
Merge remote-tracking branch 'mozilla/master' into issue_477

Conflicts:
	gaiatest/tests/settings/manifest.ini
Send passcode as a string into keyboard.
Merge remote-tracking branch 'mozilla/master' into issue_477

Conflicts:
	gaiatest/tests/settings/manifest.ini
Merge pull request #506 from askeing/issue_477

Set a passcode using Settings app for #477