buildroot

package/collectd: use 'menuconfig' instead of 'config'+'menu'

Keep the existing sub-menus, because there are a lot of entries in those
sub-menus. Using comments to separate them is not a totally satifactory
solution.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>