Updating spice-gtk blocked for the last four months

[Ralph Seichter]

Thanks for investigating this. With the latest changes by Renee Otten I
was able to update spice-gtk and virt-manager on my machine. The attempt
to open an existing QEMU VM in virt-manager results in the error message
shown below, for which I should probably open a separate bug report.
Still, it is progress of sorts, so thanks again.

{{{
Error launching details: could not get a reference to type class

Traceback (most recent call last):
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.9/share/virt-manager/virtManager/vmwindow.py", line 40, in get_instance
    cls._instances[key] = vmmVMWindow(vm)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.9/share/virt-manager/virtManager/vmwindow.py", line 82, in __init__
    self._details = vmmDetails(self.vm, self.builder, self.topwin,
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.9/share/virt-manager/virtManager/details/details.py", line 397, in __init__
    self._xmleditor = vmmXMLEditor(self.builder, self.topwin,
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.9/share/virt-manager/virtManager/xmleditor.py", line 44, in __init__
    self._init_ui()
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.9/share/virt-manager/virtManager/xmleditor.py", line 69, in _init_ui
    self._srcview = GtkSource.View()
TypeError: could not get a reference to type class
}}}