[gtk-vnc] gvncviewer.py: fix the screenshot feature

[Daniel P. Berrange <dberrange src gnome org>]

commit 8617b5c739a5f8b9e0840df8f1b7fd2e0b0b6f72
Author: Dr. Matthias St. Pierre <matthias st pierre ncp-e com>
Date:   Fri Oct 23 00:13:46 2020 +0200

    gvncviewer.py: fix the screenshot feature
    
    It seems like GdkPixbuf.Pixbuf.save() was replaced by GdkPixbuf.Pixbuf.savev(),
    which yields the following error:
    
      Traceback (most recent call last):
        File ".../gtk-vnc/examples/gvncviewer.py", line 64, in vnc_screenshot
          pix.save("gvncviewer.png", "png", { "tEXt::Generator App": "gvncviewer.py" })
      AttributeError: 'Pixbuf' object has no attribute 'save'

 examples/gvncviewer.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/examples/gvncviewer.py b/examples/gvncviewer.py
index dbe69d4..f646f1b 100755
--- a/examples/gvncviewer.py
+++ b/examples/gvncviewer.py
@@ -65,9 +65,9 @@ def set_title(vnc, window, grabbed):
     window.set_title("%s%s - GVncViewer" % (subtitle, name))
 
 def vnc_screenshot(src, ev, vnc):
-    if ev.keyval == Gdk.keyval_from_name("F11"):
+    if ev.keyval == Gdk.KEY_F11:
         pix = vnc.get_pixbuf()
-        pix.save("gvncviewer.png", "png", { "tEXt::Generator App": "gvncviewer.py" })
+        pix.savev("gvncviewer.png", "png", ["tEXt::Generator App"], ["gvncviewer.py"])
         print("Screenshot saved to gvncviewer.png")
 
     return False