[stp-pmc] Commit rights for Erica Mitchell have been expired

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

stp Committers,
Oisin Hurley has expired the commit rights for Erica Mitchell (emitchell). 
The reason for this change is:

Erica was an initial committer on the project, but has not been active
since. As such, I'm removing her as inactive according to Dev Process
section 4.7  : http://tinyurl.com/5dyxoo