server-tools/base_fontawesome/templates/assets.xml

<?xml version="1.0" encoding="utf-8" ?>
<!--
Copyright 2017 Simone Orsi
License LGPL-3.0 or later (http://www.gnu.org/licenses/lgpl.html).
-->
<odoo>

	<template id="assets_common" inherit_id="web.assets_common">
		<xpath expr="link[@href='/web/static/lib/fontawesome/css/font-awesome.css']" position="replace">
			<link rel="stylesheet" type="text/css" href="/base_fontawesome/static/lib/fontawesome-4.7.0/css/font-awesome.css" />
		</xpath>
	</template>

</odoo>