Fix updater include generation w/installclean

Since this was putting the intermediate file in obj/PACKAGING, every
installclean was removing it and triggering updater to rebuild. Instead,
use the standard generated-sources-dir. The dep file can also be removed
now that ninja will re-run the generator if the command line changes.

Test: m -j updater; m installclean; m -j updater
Test: Only change to aosp_fugu updater before/after is the debug info
Change-Id: I20928bd2049d4a3d4e21f83fd64d16cfdc541958