Re-enable running of iotests
    
    6 months and 2 QEMU release later, we want to test if they
    are more reliable now. At least we'll get better diagnostic
    of which test is hanging since the patch in
    
      https://www.mail-archive.com/qemu-devel@nongnu.org/msg887683.html
    
    is included in this QEMU
    
    Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>