[jhbuild] sysid: fix ID_LIKE logic

[Ryan Lortie <desrt src gnome org>]

commit 239c27d61b90b60282aafa01c0bb6a761223a840
Author: Ryan Lortie <desrt desrt ca>
Date:   Mon Jan 26 10:47:09 2015 +0000

    sysid: fix ID_LIKE logic
    
    .union() returns a new set.  .update() is the update-in-place version.

 jhbuild/utils/sysid.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/jhbuild/utils/sysid.py b/jhbuild/utils/sysid.py
index 40f547b..c68e0f2 100644
--- a/jhbuild/utils/sysid.py
+++ b/jhbuild/utils/sysid.py
@@ -74,7 +74,7 @@ def read_os_release():
     default_conditions.add(fields['ID'])
 
     if 'ID_LIKE' in fields:
-        default_conditions.union(fields['ID_LIKE'].split(' '))
+        default_conditions.update(fields['ID_LIKE'].split(' '))
 
     return True