Merge pull request #10918 from bwbarrett/bugfix/mailmap-cleanup

Updates to mailmap file

Author: awlauria

.mailmap

@@ -130,3 +130,7 @@ Samuel K. Gutierrez <samuel@lanl.gov> <samuel@lanl.gov>
 Tomislav Janjusic <tomislavj@nvidia.com> Tomislavj Janjusic <tomislavj@nvidia.com>
 
 William P. LePera <lepera@us.ibm.com>
+
+George Katevenis <gkatev@ics.forth.gr>
+
+Brian Barrett <brian@bbarrett.org>