Skip uninstalled package for getPackagesForUid()

If a package with sharedUserId had been setInstalled
with false, then the result of getPackagesForUid()
should not include it.

https://code.google.com/p/android/issues/detail?id=212255



Change-Id: I7b984051db34ecc2d0ef9518786d51100ab9ac79
Signed-off-by: liulvping <liulvping@xiaomi.com>