libvirt security and bug fix update

[1.1.1-29.0.1.el7_0.4]

• Replace docs/et.png in tarball with blank image
  [1.1.1-29.el7_0.4]
• qemu: blockcopy: Don’t remove existing disk mirror info (rhbz#1149078)
• qemu: copy: Accept ‘format’ parameter when copying to a non-existing img (rhbz#1149078)
• qemu: reject rather than hang on blockcommit of active layer (rhbz#1150379)
• CVE-2014-7823: dumpxml: security hole with migratable flag (CVE-2014-7823)
• Fix crash when saving a domain with type none dac label (rhbz#1171124)