Oups I did it again

git-svn-id: https://redmine.imt-atlantique.fr/svn/xaal/code/Python/branches/fork@1630 b32b6428-25c9-4566-ad07-03861ab6144f

devices/sensors/HTU21D/xaal/htu21d/gw.py

@@ -26,6 +26,9 @@ def build_dev(addr,devtype):
 
 def smooth(attribute,value,gap):
     old = attribute.value
+    if not old:
+        attribute.value = value
+    
     if not (old - gap <= value <= old + gap):
         attribute.value = value