[BUGFIX] Encryted SMTP does not work

Changes type of $TYPO3_CONF_VARS['MAIL']['transport_smtp_encrypt']
from checkbox to input field. So the user can enter a transport protocol
for connecting the SMTP server.

Change-Id: I1195d640320616234ba0be7cc0328151e44a8999
Resolves: #M17465
Reviewed-on: http://review.typo3.org/1127


Reviewed-by: Steffen Gebert <steffen.gebert@typo3.org>
Tested-by: Steffen Gebert <steffen.gebert@typo3.org>
Reviewed-by: Jigal van Hemert <jigal@xs4all.nl>
Tested-by: Jigal van Hemert <jigal@xs4all.nl>