MFC 198126: Fix a sign bug in the handling of nice priorities when computing the interactive score for a thread.
MFC 198126:
Fix a sign bug in the handling of nice priorities when computing the
interactive score for a thread.

Approved by:	re (kib)

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase