Use the right flag types when creating InstallArgs

Need to use PackageManager.INSTALL_{EXTERNAL,FORWARD_LOCKED} for
createInstallArgs instead of ApplicationInfo.FLAG_etc for the install
args to be created correctly. If certain flags conflict, there will be a
failure to delete the package.

Change-Id: Ibd8705943371596b2f2d6c24bd071b737ca74ef4