Don't spam the log during quota calculations.

We base the cache quotas on usage stats on the device. These stats,
however, can contain entries from apps which are no longer installed.
In this case, we skip its calculation and log a warning. This patch
removes the warning aspect of it, because it is a legitimate case.

Change-Id: I2a6a797966bfee007515735308535a5dcc118f03
Fixes: 36649802
Test: Manual