Update Legoktm's mailmap entry

Change-Id: I648b23e5a0eb92b796709ebda7afc5ba41d1ce44

.mailmap

@@ -44,9 +44,10 @@ Jiabao <jiabao.foss@gmail.com>
 Jon Robson <jrobson@wikimedia.org>
 Juliusz Gonera <jgonera@gmail.com>
 Juliusz Gonera <jgonera@gmail.com> <jgonera@wikimedia.org>
-Kunal Mehta <legoktm@gmail.com>
-Kunal Mehta <legoktm@gmail.com> <legoktm@member.fsf.org>
-Kunal Mehta <legoktm@gmail.com> <legoktm.wikipedia@gmail.com>
+Kunal Mehta <legoktm@debian.org>
+Kunal Mehta <legoktm@debian.org> <legoktm@member.fsf.org>
+Kunal Mehta <legoktm@debian.org> <legoktm.wikipedia@gmail.com>
+Kunal Mehta <legoktm@debian.org> <legoktm@gmail.com>
 Marielle Volz <marielle.volz@gmail.com>
 Mark A. Hershberger <mah@everybody.org>
 Mark A. Hershberger <mah@everybody.org> <mah@nichework.com>