authors.xml: my name was in duplicate.

Leaving the one without the surname. My surname is not a secret at all,
but I really don't consider it necessary anyway.
Well if some day, another dev came in with the same first name, it will
still be time to update this file. :-)

authors.xml

@@ -142,7 +142,7 @@
   <contributor role="author" last-active="2.4">Kristian Jantz</contributor>
   <contributor role="author" last-active="2.8">Javier Jardón</contributor>
   <contributor role="author" last-active="2.8">Tim Jedlicka</contributor>
-  <contributor role="author" last-active="2.8">Jehan</contributor>
+  <contributor role="author" last-active="2.10">Jehan</contributor>
   <contributor role="author documenter" last-active="2.8">Róman Joost</contributor>
   <contributor role="author" last-active="2.8">Alexander Jones</contributor>
   <contributor role="documenter" last-active="2.4">Hans de Jonge</contributor>
@@ -249,7 +249,6 @@
   <contributor role="author" last-active="2.8">Benjamin Otte</contributor>
   <contributor role="author" last-active="2.8">Petr Ovtchenkov</contributor>
   <contributor role="author" last-active="1.0">Alan Paeth</contributor>
-  <contributor role="author" last-active="2.10">Jehan Pagès</contributor>
   <contributor role="author" last-active="1.2">Jay Painter</contributor>
   <contributor role="author" last-active="2.10">Juan Palacios</contributor>
   <contributor role="artist author" last-active="2.10">Ville Pätsi</contributor>