Description of problem:
Can't remap network/profile to be 'Empty' on target DC when importing VM from data domain.

Map network to empty profile
2016-11-01 13:43:27,945 - Dummy-1 - storagedomains - DEBUG - Action request content is --  url:/ovirt-engine/api/storagedomains/009a842a-ed19-44b3-a130-b5b89f0593e4/vms/b639af6f-9204-4dc6-bc
38-f35a8c8205fc/register body:<action>
   <async>false</async>
   <cluster>
       <name>golden_env_mixed_1</name>
   </cluster>
   <grace_period>
       <expiry>10</expiry>
   </grace_period>
   <reassign_bad_macs>false</reassign_bad_macs>
   <vnic_profile_mappings>
       <vnic_profile_mapping>
           <source_network_name>C10_reg_dom1</source_network_name>
           <source_network_profile_name>C10_reg_dom1</source_network_profile_name>
       </vnic_profile_mapping>
   </vnic_profile_mappings>
</action> 


2016-11-01 13:43:27,946 - Dummy-1 - storagedomains - INFO - Using Correlation-Id: storagedomains_syncAction_024cbb3b-4305-494f
2016-11-01 13:43:28,156 - Dummy-1 - core_api - DEBUG - Request POST response time: 0.186
2016-11-01 13:43:28,157 - Dummy-1 - storagedomains - DEBUG - Cleaning Correlation-Id: storagedomains_syncAction_024cbb3b-4305-494f
2016-11-01 13:43:28,157 - Dummy-1 - api_utils - ERROR - Failed to syncAction element NOT as expected:
       Status: 400
       Reason: Bad Request
       Detail: vNic profile mapping is missing target vNic profile.


Version-Release number of selected component (if applicable):
4.1.0-0.0.master.20161031231324.git5d8702e.el7.centos.noarch + Yevgeny rpms

How reproducible:
100%

Steps to Reproduce:
1. Import VM from data domain and try to remap to an 'empty' network/profile(don't send target)

Actual results:
Failed. vNic profile mapping is missing target vNic profile

Expected results:
Should work

Additional info:
We are testing Yevgeny rpms on latest master.