Fixes the system server crash issue caused by uncatched exception.

The restat method of the StatFs may throw an IllegalArgumentException,
so we must to catch it and throw an IOException for the caller
of the trimToFit(),this fix can improve system stability.

https://code.google.com/p/android/issues/detail?id=218359



Change-Id: I54a2f569eea67d3ab628944e3586ca918ec70283
Signed-off-by: songjinshi <songjinshi@xiaomi.com>