package/freeswitch: fix build error

package/freeswitch: fix build error

Freeswitch has been tested agains tan older version of libcheck, 0.12.0
or earlier, while Buildroot has 0.15.1. With 0.13.0, the API of libcheck
has changed, and Freeswitch does not account for this.

Fixes
http://autobuild.buildroot.net/results/5db/5dbce5860f57c1457962aa295857689f49a60bc6/

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Tested-by: Heiko Thiery <heiko.thiery@gmail.com>
[yann.morin.1998@free.fr: expand commit log with the root cause]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>