[BUGFIX] "form field wizard" in flexform not saved

This patch fix a bug for wizards in flex forms.

Resolves: #69047
Releases: master
Change-Id: I2bf8f79729c2d31166c77a1a85b3e77cf03828a0
Reviewed-on: http://review.typo3.org/43741


Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>