PostgreSQL returns 'NULL::character varying' as the default value for a
field defined with 'VARCHAR(255) DEFAULT NULL'. The schema compare in
the InstallTool expects the MySQL syntax without the trailing
::character varying. Add support for this default value type to the
converter that rewrites the PostgreSQL default values to MySQL.

Resolves: #70558
Releases: master
Change-Id: If49962a3be265ca7a51e3f178a0682a9a073e9b7
Reviewed-on: http://review.typo3.org/43957


Reviewed-by: Nicole Cordes <typo3@cordes.co>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>
Reviewed-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Tested-by: Morton Jonuschat <m.jonuschat@mojocode.de>