Fix a crash in package installer

The first bug was that we were starting the install before
having the package info for the installed app. The second
was that we were calling the permission review UI despite
we were there before the user selected to install. i.e. the
user already reviewed the permissions.

bug:29197887

Change-Id: I2fac4d014dde7f7744a6b831c2b0ff510e29e8e8