sphinx: only generate zips if they are not up to date
sphinx: only generate zips if they are not up to date

Change-Id: I058043aab04c0c7f3be925f333c0f7c3bc21b3b2

dmerejkowsky/qibuild,dmerejkowsky/qibuild,aldebaran/qibuild,aldebaran/qibuild,dmerejkowsky/qibuild,aldebaran/qibuild,dmerejkowsky/qibuild,dmerejkowsky/qibuild,aldebaran/qibuild