Remove unused pick-sync dialog (<==, <==>, ==>).

services/sync/locales/en-US/pick-sync.dtd

@@ -1,9 +0,0 @@
-<!ENTITY dialog.title           "Sync with Weave">
-<!ENTITY dialog.accept          "Sync">
-
-<!ENTITY dir.caption            "Direction to sync">
-<!ENTITY myComputer.label       "[my computer]">
-<!ENTITY weaveCloud.label       "[weave cloud]">
-<!ENTITY dir.resetClient.label  "Do a fresh, full sync with the server">
-<!ENTITY dir.wipeClient.label   "Erase local data and restart with server data">
-<!ENTITY dir.wipeRemote.label   "Erase remote data and restart with local data">

services/sync/locales/en-US/pick-sync.properties

@@ -1,5 +0,0 @@
-dir.wipeClient.warning.title = Confirm Erase Local Data
-dir.wipeClient.warning = This will erase your local data.\n\nAre you sure you want to do this?
-dir.wipeRemote.warning.title = Confirm Erase Remote Data
-dir.wipeRemote.warning = This will erase your remote data.\n\nAre you sure you want to do this?
-

services/sync/modules/util.js

@@ -731,10 +731,6 @@ let Utils = {
     Utils._openChromeWindow("Status", "status.xul");
   },
 
-  openSync: function Utils_openSync() {
-    Utils._openChromeWindow("Sync", "pick-sync.xul");
-  },
-
   getErrorString: function Utils_getErrorString(error, args) {
     try {
       return Str.errors.get(error, args || null);