details: console: drop hardcoding background color as black

Submitted in https://github.com/virt-manager/virt-manager/pull/241

I couldn't get this code to change the output, tested with VNC and
spice-gtk on Fedora 34 gnome-shell x11 and XFCE. Maybe it's something
theme related. But either way this doesn't seem to be useful for the
default case anyways, so let's drop it

Signed-off-by: Cole Robinson <crobinso@redhat.com>

virtManager/details/console.py

@@ -332,11 +332,6 @@ class vmmConsolePages(vmmGObjectUI):
         self.widget("console-overlay").add_overlay(
                 self._overlay_toolbar_fullscreen.timed_revealer.get_overlay_widget())
 
-        # Make viewer widget background always be black
-        black = Gdk.Color(0, 0, 0)
-        self.widget("console-gfx-viewport").modify_bg(Gtk.StateType.NORMAL,
-                                                      black)
-
         self.widget("console-pages").set_show_tabs(False)
         self.widget("serial-pages").set_show_tabs(False)
         self.widget("console-gfx-pages").set_show_tabs(False)