[devtools] "fix" boundary condition for autofill maxvalue in an IntervalBoundConstraint is inclusive. If the min and max values happened to coincide, we would call random.choice on an empty list, which it didn't like. This is still broken in the case of BoundaryConstraint('>', minvalue), as we assume the minvalue is in the range, but that's something for another time.

--- a/devtools/fill.py	Thu Jan 28 18:02:49 2016 +0100
+++ b/devtools/fill.py	Wed Jan 06 15:27:59 2016 +0100
@@ -42,6 +42,9 @@
 from cubicweb.schema import RQLConstraint
 
 def custom_range(start, stop, step):
+    if start == stop:
+        yield start
+        return
     while start < stop:
         yield start
         start += step