modified some code to make tcp header.

modified some code to make tcp header.

I have modified for tcp header which
has 0 ~ 12 length or 8bit message length.
since previous code has potential issue for byte ordering.

Change-Id: Id2f63608442ccf85558c61dbfd631a01f59ad8b9
Signed-off-by: jihwan.seo <jihwan.seo@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/3401
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Patrick Lankswert <patrick.lankswert@intel.com>
(cherry picked from commit 27f18c55a2d55c5f9b3e3006d5ca8845f27d69a5)
Reviewed-on: https://gerrit.iotivity.org/gerrit/3519