Revert "0.4/2017-11-09--transaction_participants_url_length.xml: fix "max key length is 767 bytes" error from MySQL."

This reverts commit 7fd2125.

Unfortunately it didn't help :(

Author: php-coder

src/main/resources/liquibase/version/0.4/2017-11-09--transaction_participants_url_length.xml

@@ -5,26 +5,6 @@
 		xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
 		http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.0.xsd">
 
-	<changeSet id="modify-transaction_participants-url-charset" author="php-coder" context="scheme" dbms="mysql">
-		<!--
-			Fix for "liquibase.exception.DatabaseException:
-			Specified key was too long; max key length is 767 bytes
-			[Failed SQL: ALTER TABLE mystamps.transaction_participants MODIFY url VARCHAR(285)]".
-			See also: https://stackoverflow.com/questions/1814532/1071-specified-key-was-too-long-max-key-length-is-767-bytes
-		-->
-		<comment>
-			Change character set from utf8 to ascii for a URL field to be able to have a unique
-			constraint on a field that has length greater than 255 characters.
-		</comment>
-		
-		<sql>
-			  ALTER TABLE transaction_participants
-			       MODIFY url VARCHAR(285)
-			CHARACTER SET ascii
-		</sql>
-	
-	</changeSet>
-	
 	<changeSet id="modify-transaction_participants-url-field" author="php-coder" context="scheme">
 		<modifyDataType tableName="transaction_participants" columnName="url" newDataType="VARCHAR(285)" />
 	</changeSet>