Removing CA sample with NDK build

Removing CA sample with NDK build

CA sample that will build from gradle is submitted
This will build the APK directly using SCons and gradle
Hence removing earlier sample with NDK build

Change-Id: Icde256f08e7886ecfe1edcb434e7153aa69e0247
Signed-off-by: jnashok <jn.ashok@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/1750
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Erich Keane <erich.keane@intel.com>