Convert to new override syntax

This is the result of automated script (0.9.1) conversion:

oe-core/scripts/contrib/convert-overrides.py .

converting the metadata to use ":" as the override character instead of "_".

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>

meta-xfce/classes/xfce-git.bbclass

@@ -1,4 +1,4 @@
-do_configure_prepend() {
+do_configure:prepend() {
        cd ${S}
        NOCONFIGURE=yes ./autogen.sh
        cd ${B}