Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-2_1/rev/2766c3749a65
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Bug 1073400 - [Contacts] [ICE] When all ICE Contacts are unset the ICE Contact group list is displayed as empty

Conflicts:
	apps/communications/contacts/js/views/details.js
	apps/communications/contacts/test/marionette/ice_test.js
Bumping manifests a=b2g-bump