Check UID instead of package name when preparing VPN.

If a package is uninstalled and reinstalled, it should no longer be
considered a prepared VPN in prepare(). While the package name remains
constant in this case, the UID should not.

Bug: 17980393
Change-Id: I29edf22ebe0550a7938d5a36c746c83dc068a0f9
1 file changed