Fix a mediaserver crash caused by dereferencing a NULL pointer.

The pointer (info in method drainInputBuffer) in can be null at the point of the dereference,
but it will get updated subsequently. Thus, we should move the logging after the pointer gets updated.

related-to-bug: 6530159

Change-Id: Ifa5f19a694953af6942454e5c28cd3fa024f11d2