War on -Werror, part 12: explicit bool usage.

It may save a few cycles, but it's best to be
explicit on boolean operations, especially with
ASSERT.

src/OptionRow.cpp

@@ -216,7 +216,7 @@ RString OptionRow::GetRowTitle() const
 				const Course *pCourse = GAMESTATE->m_pCurCourse;
 				StepsType st = GAMESTATE->GetCurrentStyle()->m_StepsType;
 				const Trail* pTrail = pCourse->GetTrail( st );
-				ASSERT( pTrail );
+				ASSERT( pTrail != NULL );
 				pTrail->GetDisplayBpms( bpms );
 			}