[stp-pmc] Commit rights for Johnson Ma have been expired

[emo@xxxxxxxxxxx (portal on behalf of emo)]

stp Committers,
Oisin Hurley has expired the commit rights for Johnson Ma (jma).  The
reason for this change is:

Johnson made a considerable amount of commits in 2006 and 2007, but has not
been active in 2008. As such, I'm removing him as inactive according to Dev
Process section 4.7  : http://tinyurl.com/5dyxoo