Our extensions get disabled in the Tor Browser 7.0a4 release candidate

Testing the release candidate for Tor Browser 7.0a4 on a 64bit Linux machine results in disabled extensions on start-up with

1494766438500	addons.xpi-utils	DEBUG	New add-on torbutton@torproject.org installed in app-profile
1494766438600	addons.xpi-utils	WARN	Disabling foreign installed add-on torbutton@torproject.org in app-profile
1494766438600	DeferredSave.extensions.json	DEBUG	Save changes
1494766438600	addons.xpi-utils	DEBUG	New add-on {73a6fe31-595d-460b-a920-fcc0f8843232} installed in app-profile
1494766438600	DeferredSave.extensions.json	DEBUG	Starting timer
1494766438700	addons.xpi-utils	WARN	Disabling foreign installed add-on {73a6fe31-595d-460b-a920-fcc0f8843232} in app-profile
1494766438700	DeferredSave.extensions.json	DEBUG	Save changes
1494766438700	addons.xpi-utils	DEBUG	New add-on https-everywhere-eff@eff.org installed in app-profile
1494766438700	DeferredSave.extensions.json	DEBUG	Starting write
1494766438700	DeferredSave.extensions.json	DEBUG	Write succeeded
1494766438700	addons.xpi-utils	DEBUG	XPI Database saved, setting schema version preference to 19
1494766438800	addons.xpi-utils	WARN	Disabling foreign installed add-on https-everywhere-eff@eff.org in app-profile
1494766438800	DeferredSave.extensions.json	DEBUG	Save changes
1494766438800	addons.xpi-utils	DEBUG	New add-on tor-launcher@torproject.org installed in app-profile
1494766438800	DeferredSave.extensions.json	DEBUG	Starting timer
1494766438800	addons.xpi-utils	WARN	Disabling foreign installed add-on tor-launcher@torproject.org in app-profile

This blocks the 7.0a4 release.