Middle name seems to be getting break when use in Individual strict contact matching rule.

When we want to configure individual middle name in strict rule we get following backtrace.

Steps :
1. Edited Individual Strict Rule in Find and Merge Duplicate Contacts and added following fields and weight
Field Name Weight
First Name 5
Last Name 5
Email 5
Middle Name 5
Weight Threshold to Consider Contacts 'Matching': 15

After hitting save got following Error :

Database Error Code: Key column 'middle_name_' doesn't exist in table, 1072

[debug_info] => CREATE INDEX dedupe_index_middle_name_ ON civicrm_contact (middle_name_) [nativecode=1072 ** Key column 'middle_name_' doesn't exist in table]
[type] => DB_Error
[user_info] => CREATE INDEX dedupe_index_middle_name_ ON civicrm_contact (middle_name_) [nativecode=1072 ** Key column 'middle_name_' doesn't exist in table]
[to_string] => [db_error: message="DB Error: a515ac9c2796ca0e23adbe92c68fc9fc" code=0 mode=callback callback=CRM_Core_Error::handle prefix="" info="CREATE INDEX dedupe_index_middle_name_ ON civicrm_contact (middle_name_) [nativecode=1072 ** Key column 'middle_name_' doesn't exist in table]"]

/home/vijay/public_html/drupal/sites/all/modules/civicrm/packages/DB/DataObject.php, _query, 1587
/home/vijay/public_html/drupal/sites/all/modules/civicrm/CRM/Core/DAO.php, query, 144
/home/vijay/public_html/drupal/sites/all/modules/civicrm/CRM/Core/BAO/SchemaHandler.php, query, 346
/home/vijay/public_html/drupal/sites/all/modules/civicrm/CRM/Admin/Form/DedupeRules.php, createIndexes, 178
/home/vijay/public_html/drupal/sites/all/modules/civicrm/CRM/Core/Form.php, postProcess, 247
/home/vijay/public_html/drupal/sites/all/modules/civicrm/CRM/Core/StateMachine.php, mainProcess, 166