Delete custom field: DB Error Code: Error on rename of... (errno: 152),

Deleting a custom field of type 'contact reference' produces an error. Seems to be related to renaming the foreign key.

Steps to recreate on the demo site:
1. Create a custom field of type 'contact reference'
2. Delete it

Error output:
unrecoverable error
Sorry. A non-recoverable error has occurred.
DB Error: a515ac9c2796ca0e23adbe92c68fc9fc
Database Error Code: Error on rename of './civicrm_demo_drupal/civicrm_value_constituent_information_1' to './civicrm_demo_drupal/#sql2-11cd-1b58c7' (errno: 152), 1025

Error Details:
Array
(
[callback] => Array
(
[0] => CRM_Core_Error
[1] => handle
)

[code] => a515ac9c2796ca0e23adbe92c68fc9fc
[message] => DB Error: a515ac9c2796ca0e23adbe92c68fc9fc
[mode] => 16
[debug_info] => ALTER TABLE civicrm_value_constituent_information_1 DROP COLUMN `related_4`, DROP FOREIGN KEY FK_civicrm_value_constituent_information_1_related_4 [nativecode=1025 ** Error on rename of './civicrm_demo_drupal/civicrm_value_constituent_information_1' to './civicrm_demo_drupal/#sql2-11cd-1b58c7' (errno: 152)]
[type] => DB_Error
[user_info] => ALTER TABLE civicrm_value_constituent_information_1 DROP COLUMN `related_4`, DROP FOREIGN KEY FK_civicrm_value_constituent_information_1_related_4 [nativecode=1025 ** Error on rename of './civicrm_demo_drupal/civicrm_value_constituent_information_1' to './civicrm_demo_drupal/#sql2-11cd-1b58c7' (errno: 152)]
[to_string] => [db_error: message="DB Error: a515ac9c2796ca0e23adbe92c68fc9fc" code=0 mode=callback callback=CRM_Core_Error::handle prefix="" info=" ALTER TABLE civicrm_value_constituent_information_1 DROP COLUMN `related_4`, DROP FOREIGN KEY FK_civicrm_value_constituent_information_1_related_4 [nativecode=1025 ** Error on rename of './civicrm_demo_drupal/civicrm_value_constituent_information_1' to './civicrm_demo_drupal/#sql2-11cd-1b58c7' (errno: 152)]"]
)