Bug 946047: Add nfc read only permissions to Settings UI to allow navigator.mozNfc DOM to be created.

This fix is needed for apps using NFC if "HasNfcSupport" is added to the navigator MozNfc WebIDL.

Conflicts:
	apps/settings/manifest.webapp
Merge pull request #14368 from svic/rebase-df070d4e-NFC-Settings-permission

Bug 946047: Add nfc read only permissions to Settings UI to allow navigator.mozNfc DOM to be created. r=evelyn