Fix AppStandbyController flag.

mUnexempted... was using the value of the EXEMPTED_... flag. The default
values were the same, but this would have caused a problem if we tried
to update the value via a flag.

Also removing deprecated flags.

Bug: 141645789
Test: N/A
Change-Id: I2ace1b510b2d7f5d6f92c16dd6302ae4e5525456