www/firefox-esr: update to 52.2.0

Changes: https://www.mozilla.org/firefox/52.2.0/releasenotes/
Changes: https://hg.mozilla.org/releases/mozilla-esr52/shortlog/FIREFOX_52_2_0esr_RELEASE
Security: 6cec1b0a-da15-467d-8691-1dea392d4c8d
MFH: 2017Q2