Clean up ota-apex whenever we reserve space

Whenever we reserve space for OTA, it means there is a new OTA update
incoming. As such, any existing '.ota.apex' files in
/data/apex/decompressed belong to a previous OTA update.

We should clean up these old '.ota.apex' files so that there is enough
space for reservation.

Bug: 172911822
Test: atest ApexTestCases
Change-Id: Ief90c2df6cf1f6b488cf0b1793445a53c1ab9130
Merged-In: Ief90c2df6cf1f6b488cf0b1793445a53c1ab9130
(cherry picked from commit 6c6a6e00014eb0042a13a67533790edb51298f25)
2 files changed