CRM-12647 - Simplify. Separate field-rewriting from XML encoding

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* CRM-12647: Customization export/import crashes on "&"
  http://issues.civicrm.org/jira/browse/CRM-12647

CRM/Utils/Migrate/Export.php

@@ -373,8 +373,9 @@ AND    entity_id    IS NULL
             exit();
           }
         }
+
+        $value = $object->$name;
         if ($name == 'field_name') {
-          $value = $object->$name;
           // hack for profile field_name
           if (substr($value, 0, 7) == 'custom_') {
             $cfID = substr($value, 7);
@@ -382,9 +383,6 @@ AND    entity_id    IS NULL
             $value = "custom.{$tableName}.{$columnName}";
           }
         }
-        else {
-          $value = str_replace(CRM_Core_DAO::VALUE_SEPARATOR, self::XML_VALUE_SEPARATOR, $object->$name);
-        }
         $keyValues[$name] = $value;
       }
     }
@@ -392,7 +390,7 @@ AND    entity_id    IS NULL
     // We're ready to format $keyValues as XML
     $xml = "    <$objectName>";
     foreach ($keyValues as $k => $v) {
-      $xml .= "\n      " . $this->renderTextTag($k, $v);
+      $xml .= "\n      " . $this->renderTextTag($k, str_replace(CRM_Core_DAO::VALUE_SEPARATOR, self::XML_VALUE_SEPARATOR, $v));
     }
     if ($additional) {
       $xml .= $additional;