Description of problem:

Editing some sub attribute of vm's or template's initialization attribute via API will override all other sub_attributes e.g.

say you have a template with:

<initialization>
<host_name>foo.bar.com</host_name>
<dns_servers>1.2.3.4</dns_servers
</initialization>

and now you want to change the dns_servers value:

PUT https://{engine_url}/ovirt-engine/api/templates/{template_id}

<template>
<initialization>
<dns_servers>5.6.7.8</dns_servers
</initialization>
</template>

Actual result:
Result is that host_name is overridden and is now blank, only dns_servers will be updated.
This happens with both vm/template entities.

Expected result:
Only the sub attribute given in the PUT call is changed while all other initialization sub attributes' values persist.

Version-Release number of selected component (if applicable):
ovirt-engine-4.0.0-0.0.master.20160405102116.git3819ab7.el7.centos.noarch

How reproducible:
always

No log is helpful in this case and bug is easy to re produce.