[C++] Fix a off-by-one error in StripShellComment
[C++] Fix a off-by-one error in StripShellComment

google/kati,danw/kati,danw/kati,google/kati,shinh/kati,danw/kati,shinh/kati,danw/kati,shinh/kati,shinh/kati,google/kati,google/kati,shinh/kati,google/kati,shinh/kati,danw/kati,danw/kati