Do not try to handle OOM exceptions in logging

We duplicate quite some code here in an attempt to still print
messages, even in OOM situations. However, we've in general given up
on handling OOM exceptions gracefully in Qt: On modern systems
you hardly reach the point of not being able to allocate (smaller)
chunks in the first place, since the system will usually overcommit,
or bring the system to halt by heavy paging.

In 7cafb62538661863e5c we removed already similar logic in QDebug
class.

Change-Id: I4f84641c41c5e230a60dc0b7a5b0a13dec20f90f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>