Fix some dodgy synchronisation.

Change-Id: I829d5e34edaf30bcdd171b693a5ad44f053f0430
Reviewed-on: http://gerrit.dmdirc.com/3829
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Chris Smith <chris@dmdirc.com>

src/com/dmdirc/addons/ui_swing/components/statusbar/MessagePopup.java

@@ -106,7 +106,7 @@ class MessagePopup extends StatusbarTogglePanel<JLabel> {
      * @param message to add
      */
     public void addMessage(final StatusMessage message) {
-        synchronized (message) {
+        synchronized (messages) {
             messages.add(message);
         }
     }

src/com/dmdirc/addons/ui_swing/dialogs/error/ErrorTableModel.java

@@ -66,7 +66,7 @@ public final class ErrorTableModel extends AbstractTableModel implements ErrorLi
      * @param errors List of errors
      */
     public void setErrors(final List<ProgramError> errors) {
-        synchronized (errors) {
+        synchronized (this.errors) {
             this.errors.clear();
             this.errors.addAll(errors);
         }