C: add Robert Kroeger (Google CLA)

Change-Id: I6babd90350fb07e2336d63fde2fbafb81dce812b
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index 07f3005..28ea250 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -63,8 +63,9 @@
 Pawel Szczur <pawelszczur@gmail.com>
 Philio <phil@bayfmail.com>
 Ranveer <ranveerkunal@gmail.com>
-Robert Obryk <robryk@gmail.com>
 Robert Hencke <robert.hencke@gmail.com>
+Robert Kroeger <rjkroege@liqui.org>
+Robert Obryk <robryk@gmail.com>
 Ryan Barrett <camlistore@ryanb.org>
 Salman Aljammaz <s@0x65.net>
 Sarath Lakshman <sarathlakshman@slynux.com>