qemu-2.3.1-7.fc22 seems to break interaction with the guest spice-vdagent. There's even reports of this hanging windows VMs
The issue is that the package was built against spice-server 0.12.6, but if it runs against an older spice-server, everything misbehaves. More info over here: https://bugzilla.redhat.com/show_bug.cgi?id=1271153#c30
Pushing spice 0.12.6 to stable will more or less fix this, but anyone hitting issues in the interim can do:
sudo yum --enablerepo=updates-testing update spice\*