Description:
Since MySQL 5.1.53 (with the fix for Bug http://bugs.mysql.com/36742) all host names written to system tables by administrative commands should be converted to lower case form before hitting the storage layer (as host names are actually case insensitive).

CREATE SERVER still stores host names with upper case characters as-is

How to repeat:

mysql> CREATE SERVER FooBar FOREIGN DATA WRAPPER mysql OPTIONS (USER 'Remote', HOST 'FooBar', DATABASE 'test');

Query OK, 1 row affected (0,00 sec)

mysql> select Server_Name, Host FROM mysql.servers;

+-------------+--------+

| Server_Name | Host   |

+-------------+--------+

| FooBar      | FooBar |

+-------------+--------+

1 row in set (0,00 sec)

Suggested fix:
Convert host names for mysql.servers to lower case before actually hitting the table like it is done with the other system tables since MySQL 5.1.53