Bug 855175 - [Contacts] Add contact: After clicked an input field and switched to the Lable page directly, the keyboard did not hide.

We used the mozKeyboard API to remove the focus in the goToSelectTag function.
See the code:
https://github.com/mozilla-b2g/gaia/blob/master/apps/communications/contacts/js/contacts.js#L404

But we didn't defined the keyboard permission in the manifest.webapp.
See the code:
https://github.com/mozilla-b2g/gaia/blob/master/apps/communications/manifest.webapp#L69

We need to define a keyboard permission in the manifest.webapp for using the mozKeyboard API.