[CLN-list] CLN patch 3 for MSVC

Hi, here is a simple one correcting some unclear code (at least from the point of view of the pedantic MSVC compiler). 1. Added const because the original declaration in the header file also has it 2. Added double to resolve ambiguities in which log() function is meant With this patch and the two others I sent earlier CLN compiles with MSVC and all tests pass successfully. Jan