Set classes to use Messages getter in plugin instance.

src/main/java/fr/xephi/authme/process/register/ProcessSyncEmailRegister.java

@@ -20,7 +20,7 @@ public class ProcessSyncEmailRegister implements Runnable {
     protected final Player player;
     protected final String name;
     private final AuthMe plugin;
-    private final Messages m = Messages.getInstance();
+    private final Messages m;
 
     /**
      * Constructor for ProcessSyncEmailRegister.
@@ -29,6 +29,7 @@ public class ProcessSyncEmailRegister implements Runnable {
      * @param plugin AuthMe
      */
     public ProcessSyncEmailRegister(Player player, AuthMe plugin) {
+        this.m = plugin.getMessages();
         this.player = player;
         this.name = player.getName().toLowerCase();
         this.plugin = plugin;