[FIX] eval(label) fails if label is not a str.

bzr revid: florent.xicluna@gmail.com-20120119215758-yflsp1cjz997o2r8

openerp/addons/base/ir/ir_ui_view.py

@@ -125,7 +125,7 @@ class view(osv.osv):
 
     def graph_get(self, cr, uid, id, model, node_obj, conn_obj, src_node, des_node, label, scale, context=None):
         if not label:
-            label = []
+            label = '[]'
         nodes=[]
         nodes_name=[]
         transitions=[]