Convert to new override syntax

This is the result of automated script conversion:

scripts/contrib/convert-overrides.py <oe-core directory>

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

(From OE-Core rev: 42344347be29f0997cc2f7636d9603b1fe1875ae)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/packagegroup.bbclass

@@ -32,7 +32,7 @@ python () {
                     for suffix in types]
         d.setVar('PACKAGES', ' '.join(packages))
     for pkg in packages:
-        d.setVar('ALLOW_EMPTY_%s' % pkg, '1')
+        d.setVar('ALLOW_EMPTY:%s' % pkg, '1')
 }
 
 # We don't want to look at shared library dependencies for the