Description of problem:
deleting a host with incomplete XML 

Version-Release number of selected component (if applicable):
libvirt-1.1.1-2.el7.x86_64

How reproducible:
You may rely on it.

Steps to Reproduce:
1. Have a network with a host in the dhcp section:
<network>
  <name>default</name>
...
  <ip address='192.168.122.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.122.2' end='192.168.122.254' />
      <host mac='12:34:56:78:90:ab' name='aaa' ip='192.168.122.123' />
    </dhcp>
  </ip>
</network>

2. virsh # net-update default delete ip-dhcp-host "<host ip='192.168.122.123'/>"
error: Failed to update network default
error: XML error: Static host definition in IPv4 network 'default' must have mac or name attribute

Expected results:
The host is deleted since it's uniquely identified by the IP.

Additional info:
Fixed upstream by:
commit cf602e7c597830a2d949017fe71f06b5f542c805
Author:     Ján Tomko <jtomko>
AuthorDate: 2013-07-31 13:25:59 +0200
Commit:     Ján Tomko <jtomko>
CommitDate: 2013-08-07 16:31:12 +0200

    Reverse logic allowing partial DHCP host XML
    
    Before, missing attributes were only OK when adding entries;
    modification and deletion required all of them.
    
    Now, only deletion works with missing attributes, as long as
    the host is uniquely identified.

git describe: v1.1.1-76-gcf602e7

The commit message is not completely accurate: Even though partial entries were parsed as correct when adding hosts by the function the commit is fixing, they were rejected later when the whole network XML was verified.