modified target message type related blockwise transfer.

modified target message type related blockwise transfer.

according to a spec, uses of the block options in conjunction
with multicast messages are for further study. so I modified to not
pass the blockwise transfer logic in case of the multicast message.

Change-Id: I2913dc7fc608e6da007071fd325c76931cf02325
Signed-off-by: hyuna0213.jo <hyuna0213.jo@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/6253
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: jihwan seo <jihwan.seo@samsung.com>
Reviewed-by: Ashok Babu Channa <ashok.channa@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/7375
Reviewed-by: Jon A. Cruz <jon@joncruz.org>