Be more specific when toasting "Success!"

Closes #4871
//FREEBIE

src/org/thoughtcrime/securesms/ExportFragment.java

@@ -134,7 +134,7 @@ public class ExportFragment extends Fragment {
           break;
         case SUCCESS:
           Toast.makeText(context,
-                         context.getString(R.string.ExportFragment_success),
+                         context.getString(R.string.ExportFragment_export_successful),
                          Toast.LENGTH_LONG).show();
           break;
       }

src/org/thoughtcrime/securesms/util/SaveAttachmentTask.java

@@ -111,7 +111,7 @@ public class SaveAttachmentTask extends ProgressDialogAsyncTask<SaveAttachmentTa
                        Toast.LENGTH_LONG).show();
         break;
       case SUCCESS:
-        Toast.makeText(context, R.string.ConversationFragment_success_exclamation,
+        Toast.makeText(context, R.string.ConversationFragment_file_saved_successfully,
             Toast.LENGTH_LONG).show();
         break;
       case WRITE_ACCESS_FAILURE: