Update Chapel help message for --log
Update Chapel help message for --log

The old version said the definition of the letters to use lived in log.h.  That
is no longer true, they live in runpasses.cpp.  Update the help message to point
to the right file.

chizarlicious/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,hildeth/chapel,hildeth/chapel,chizarlicious/chapel,chizarlicious/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,chizarlicious/chapel,hildeth/chapel,hildeth/chapel,chizarlicious/chapel,chizarlicious/chapel,hildeth/chapel,hildeth/chapel,chizarlicious/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,hildeth/chapel,CoryMcCartan/chapel