Fix issue #13199860: PRE_BOOT_COMPLETED intent is...

...broadcasted repeatedly at every boot time

Remember the last done pre-boot receivers, so that if we have
a new pre boot receiver appearing (without the platform version
changing), when we re-write the file of done receivers it will
contain all of them, not just the new one.

Change-Id: I4ed3478edc549d4b023ec4b3719111bc4d970ae4