catching no data error from gdbs centring lookup

kis_tools/gris/GrisFitsFile.py

@@ -118,6 +118,8 @@ class GrisFitsFile(FitsFile):
                 gdbs_usable = False
         except IOError:
             gdbs_usable = False
+        except ValueError:
+            gdbs_usable = False
 
         if not gdbs_usable:
             # Determined from offset between uncentered and cross_correlated data