List documents with tag, rename/delete tag fails with specific versions of MySQL5

Example of incrimined version:

mysqld  Ver 5.0.51a-24-log for debian-linux-gnu on i486 ((Debian))

Bugs are all due to getDocumentsWithTag() which fails to retrieve results.

See also:

• http://markmail.org/message/zmku4w4ust3jev7d
• http://markmail.org/message/by5atdgvpton4jkw