Do not try to build OICMiddle examples on arduino.

Do not try to build OICMiddle examples on arduino.

When the target OS is arduino, avoid attempting to build the OICMiddle
example since it is C++ and not supported for that platform.

Change-Id: I054ab220214c707954f4bf3cf17b6667ee9a82a6
Signed-off-by: Jon A. Cruz <jonc@osg.samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/517
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Joseph Morrow <joseph.l.morrow@intel.com>
Reviewed-by: Erich Keane <erich.keane@intel.com>