[BUGFIX] ADOdb: Set charset properly

Using ADOdb, the charset might not be set properly, since every
database driver needs to define their own "SetCharSet" method. Every
driver extends from ADOConnection. "SetCharSet" of this class just
returns FALSE.

Resolves: #61738
Releases: master, 6.2
Change-Id: Ia9cef4fa3da76523de883ed7faa5aaebde4b9e9b
Reviewed-on: http://review.typo3.org/32883
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>