Change Peter Waller's canonical e-mail address

Docker-DCO-1.1-Signed-off-by: Peter Waller <p@pwaller.net> (github: pwaller)

.mailmap

@@ -93,3 +93,4 @@ Nathan LeClaire <nathan.leclaire@docker.com> <nathanleclaire@gmail.com>
 <marc@marc-abramowitz.com> <msabramo@gmail.com>
 Matthew Heon <mheon@redhat.com> <mheon@mheonlaptop.redhat.com>
 <bernat@luffy.cx> <vincent@bernat.im>
+<p@pwaller.net> <peter@scraperwiki.com>

AUTHORS

@@ -421,7 +421,7 @@ Paul Nasrat <pnasrat@gmail.com>
 Paul <paul9869@gmail.com>
 Paul Weaver <pauweave@cisco.com>
 Peter Braden <peterbraden@peterbraden.co.uk>
-Peter Waller <peter@scraperwiki.com>
+Peter Waller <p@pwaller.net>
 Phillip Alexander <git@phillipalexander.io>
 Phil Spitler <pspitler@gmail.com>
 Phil <underscorephil@gmail.com>