Distinct User-Agent for the replicator

closes COUCHDB-2728
diff --git a/src/couch_replicator_api_wrap.hrl b/src/couch_replicator_api_wrap.hrl
index 1a6f27a..eee04da 100644
--- a/src/couch_replicator_api_wrap.hrl
+++ b/src/couch_replicator_api_wrap.hrl
@@ -17,7 +17,7 @@
     oauth = nil,
     headers = [
         {"Accept", "application/json"},
-        {"User-Agent", "CouchDB/" ++ couch_server:get_version()}
+        {"User-Agent", "CouchDB-Replicator/" ++ couch_server:get_version()}
     ],
     timeout,            % milliseconds
     ibrowse_options = [],