initial project creation does not accept modification of publish flags

[dirkmueller]

Issue description

By creating a new project, it is not possible to create it with publishing disabled using this cmdline:

$ osc api -T /tmp/meta /source/home:suse-cloud-ci:rpm-packaging-sles12-Master-fa5dece6da3baa994270a45a377eed383afafed8-test2/_meta

When retrieving the meta, it has been accepted except for the publishing flags. in order to accept the publish flag to disabled, it needs to be transmitted again, on 2nd commit it is possible to disable publishing.

is this intentional? the meta is this

<project name="home:suse-cloud-ci:rpm-packaging-sles12-Master-fa5dece6da3baa994270a45a377eed383afafed8-test2">
  <title>Autogenerated CI project</title>
  <description>

This project tests the following Zuul Change IDs: 640587,3

Branch used: master

Project used: openstack/rpm-packaging

  </description>
  <link project="Cloud:OpenStack:Upstream:Master"/>
  <url>
http://ci.opensuse.org/job/openstack-rpm-packaging-sles12-Master/7298/
  </url>
  <person userid="suse-cloud-ci" role="maintainer"/>
<publish>
<disable/>
</publish>
  <repository name="standard" rebuild="direct" block="local" linkedbuild="localdep">
    <path project="Cloud:OpenStack:Upstream:Master" repository="standard"/>
    <arch>x86_64</arch>
  </repository>
</project>

Expected Result

I would expect to be able to disable pushling without repeated posts of the meta.