it was accessing the details of the Log class directly. Let it go
through the channel class instead.
This also discovered a bug when we were setting but not clearing the log
options when enabling a channel.
llvm-svn: 297053
All references to Host and Core have been removed, so this
class can now safely be lowered into Utility.
Differential Revision: https://reviews.llvm.org/D30559
llvm-svn: 296909