add git .mailmap file and use it

.mailmap

@@ -0,0 +1,2 @@
+Sergio Cazzolato <sergiocazzolato@gmail.com> sergio-j-cazzolato <sergio.cazzolato@canonical.com>
+John R. Lenton <jlenton@gmail.com> John Lenton <chipaca@users.noreply.github.com> 

cmd/snap/cmd_blame_generated.go

@@ -3,5 +3,5 @@ package main
 // generated by mkauthors.sh; do not edit
 
 func init() {
-	authors = []string{"Mark Shuttleworth", "Gustavo Niemeyer",  "Sergio Schvezov", "Simon Fels", "Kyle Fazzari", "Sergio Cazzolato", "Leo Arias", "Gustavo Niemeyer", "Federico Gimenez", "Maciej Borzecki", "Jamie Strandboge", "Pawel Stolowski", "John R. Lenton", "Samuele Pedroni", "Zygmunt Krynicki", "Michael Vogt",}
+	authors = []string{"Mark Shuttleworth", "Gustavo Niemeyer", "Sergio Schvezov", "Simon Fels", "Kyle Fazzari", "Leo Arias", "Sergio Cazzolato", "Gustavo Niemeyer", "Federico Gimenez", "Maciej Borzecki", "Jamie Strandboge", "Pawel Stolowski", "John R. Lenton", "Samuele Pedroni", "Zygmunt Krynicki", "Michael Vogt"}
 }

mkauthors.sh

@@ -36,13 +36,9 @@ if [ ! -d .git ]; then
     exit
 fi
 
-# "John Lenton" and "John R. Lenton" are the same guy
-raw_authors="$(git shortlog -s|sort -n|grep -v "John Lenton"|tail -n14|cut -f2)"
+raw_authors="$(git shortlog -s|sort -n|tail -n14|cut -f2)"
 authors=""
 while read -r author; do
-    if [ "$author" = "sergio-j-cazzolato" ]; then
-        author="Sergio Cazzolato"
-    fi
     authors="$authors \"$author\","
 done <<< "$raw_authors"
 
@@ -57,3 +53,4 @@ func init() {
 }
 EOF
 
+go fmt $GO_GENERATE_BUILDDIR/cmd/snap/cmd_blame_generated.go >/dev/null