CMFileManager: Remove top & bottom padding in FS info dialog

There are visible borders to the scrollview, so the user
expects the content to scroll all the way to the borders.

Having the top & bottom padding makes the actual vertical
scroll distance shorter than what the user expects it to be.

Hence, remove the excessive padding.

RM-290

Change-Id: Ibd6609d8d7fefe1cac101e641264779055fe2ba9
(cherry picked from commit 9ba628b7)