Enable django-cachalot by default, requires django<2.2, refs #607

1 job for release-3 in 7 minutes and 16 seconds
Status Job ID Name Coverage
  Test
failed #2608
make_test

00:07:16

 
Name Stage Failure
failed
make_test Test
AttributeError: 'ExtraJoinRestriction' object has no attribute 'rhs'

----------------------------------------------------------------------
Ran 203 tests in 97.100s

FAILED (errors=3)
build/makefilet/include/python.mk:79: recipe for target 'test-python' failed
make: *** [test-python] Error 1
ERROR: Job failed: exit code 1