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

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https://hg.mozilla.org/integration/gaia-1_4/rev/a1189d931482
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Merge pull request #20121 from timdream/keyboard-hide-lock

Bug 1018335 - removeFocus() when the screen is locked, r=rudyl
Conflicts:
	apps/system/js/keyboard_manager.js
	apps/system/test/unit/keyboard_manager_test.js
Bumping manifests a=b2g-bump