Squashed commit of the following:

commit 85585eb0860e52a3dc3b8efe57ef8b30ee35c98d
Author: Suchi Amalapurapu <asuchitra@google.com>
Date:   Thu May 7 11:59:24 2009 -0700

    Remove new error code in PackageManager.
    Remove version check in installation code path. Let the install continue irrespective of version number.
    Check if data needs to be wiped(for downgrades only) in uninstallation code path.
    Also remove only code and resources when checking for updated system packages(via ota)
    Add version attribute when persisting package settings

commit f90797348c5170e6263d249e4fc77f1c0328eb27
Author: Suchi Amalapurapu <asuchitra@google.com>
Date:   Thu May 7 10:54:07 2009 -0700

    remove trailing white spaces
    hide new install code in PackageManager

commit 397eb81265160f73caf9827d381ed6622041d54e
Author: Suchi Amalapurapu <asuchitra@google.com>
Date:   Thu May 7 10:33:23 2009 -0700

    Add version check in install and uninstall code paths.
    New error code for invalid upgrades in PackageManager