[sysadmin-bin] fix property check

[Olav Vitters <ovitters src gnome org>]

commit f29d3e4db423fb1c94fcf445f439bcf2109d9a50
Author: Olav Vitters <olav vitters nl>
Date:   Sun Aug 3 10:30:02 2014 +0200

    fix property check

 git/validate-doap |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/git/validate-doap b/git/validate-doap
index cef8b6c..4fe67cf 100755
--- a/git/validate-doap
+++ b/git/validate-doap
@@ -88,8 +88,8 @@ for node in nodes:
 
     # ensure required string literal properties exist
     for prop in required_literal_properties:
-        prop_value = node.find_property((DOAP, ))
-        if not prop_value or not is_literal(prop_value):
+        prop_value = node.find_property((DOAP, prop))
+        if prop_value is None or not is_literal(prop_value):
             die("%s property is required and should be a string literal" % prop)
 
     have_maintainer = False