soft-sensor-manager: libSSMCore.so: add missing depending library

soft-sensor-manager: libSSMCore.so: add missing depending library

libSSMCore.so also depends on libdl.so, this patch adds these
dependencies to the build.

Without this the dynamic loader will not automatically load these
libraries and it could result in unresolved dependencies at runtime.

Change-Id: I76faff46fe96caef75fb6673c7e83d62b15b8489
Signed-off-by: Hauke Mehrtens <hauke.mehrtens@lantiq.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/1796
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>