Don't kill apps receiving OP_REQUEST_INSTALL_PACKAGES.

We used to kill these apps to give them the correct OBB mount view; but
very few apps use OBBs in the first place, and those that do can
manually restart to make sure they have the correct access permissions.

Bug: 157493954
Bug: 157674306
Test: atest CtsPackageInstallTestCases
Change-Id: Ia97c9f70b4184edf83c030b8a8ee0e5c7de127ec