Description of problem:
Unspecified sub-template is chosen to create VM Pool when template is specified by name.

Version-Release number of selected component (if applicable):
4.0 master, commit 5e447e0

How reproducible:
Based on order of rows returned from DB

Steps to Reproduce:
1. Create multiple sub-versions of template "t1"
2. REST request
POST /ovirt-engine/api/vmpools HTTP/1.1
Host: localhost:8080
Authorization: Basic YWRtaW5AaW50ZXJuYWw6YQ==
Content-Type: application/xml

<vm_pool>
    <name>pool1</name>
    <cluster>
        <name>Default</name>
    </cluster>
    <template>
        <name>t1</name>
    </template>
</vm_pool>

Actual results:
Pool is created. However the sub-version of template that is picked to base vm pool on depends on order of records returned by "GetVmTemplateByVmtName" stored procedure.

Expected results:
Either the base template or the latest template is always selected.

Additional info:
see: org.ovirt.engine.api.restapi.resource.BackendVmPoolsResource#getVmTemplate