[IOT-1779] Windows: fix linker errors for SECURED=0

[IOT-1779] Windows: fix linker errors for SECURED=0

The recently-added octbstack.dll exports from octbstack_product_with_tcp
were actually not available when SECURED=0.

Also, move the larger SConscript if/else paths to the 'else' branch,
for easier reading of these two nested if/else statements.

Change-Id: I66821e51c2beef2f2fbad2755a5f361ba836d892
Signed-off-by: Dan Mihai <Daniel.Mihai@microsoft.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/16807
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Dave Thaler <dthaler@microsoft.com>
Reviewed-by: Phil Coval <philippe.coval@osg.samsung.com>