Fix request #7455: Default values are not submitted a new artifact with SOAP
Web behaviour:
if user can submit fields with default value but leaves them blank/ null, the fields are not set to default value.
SOAP and REST:
if user can submit fields with default values, the fields are set default values except if it is explicitely declared in SOAP call.

Change-Id: Ifd6c959897dbd9bbc06447fc081e8ef8e1a2a788
Merge commit 'refs/changes/26/3026/4' of ssh://gerrit.tuleap.net:29418/tuleap into HEAD

* ssh://gerrit.tuleap.net:29418/tuleap:
  Fix request #7455: Default values are not submitted a new artifact with SOAP Web behaviour: if user can submit fields with default value but leaves them blank/ null, the fields are not set to default value. SOAP and REST: if user can submit fields with default values, the fields are set default values except if it is explicitely declared in SOAP call.

Change-Id: I1fd16f46af18b1ef78f292ca2f53d3be8d8a37ca
This is Tuleap 7.5.99.13

Change-Id: Ib0f274fe2c723db8377b336481bf778c7a445d49