Update NDK build with common source location change

Update NDK build with common source location change

oic_malloc and oic_string are moved to resource/c_common directory
in the patch https://gerrit.iotivity.org/gerrit/#/c/1163/
Updating android make file with the changes to fix the build

Change-Id: I297b6a25ee6a7fd744174194f9e37a877ba7cd57
Signed-off-by: jnashok <jn.ashok@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/1191
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jaehong Jo <jaehong.jo@samsung.com>
Reviewed-by: Hyuna Jo <hyuna0213.jo@samsung.com>
Reviewed-by: Erich Keane <erich.keane@intel.com>