Merge branch 'fix_mpi_kl' into 'NIFTy_5'

Fix mpi kl

See merge request !366
9 jobs for more_operator_checks in 7 minutes and 39 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build Docker
passed #962582
build_docker_from_cache

00:00:17

 
  Test
passed #962584
test_mpi

00:05:05

passed #962583
test_serial

00:05:52

82.0%
 
  Demo Runs
passed #962589
run_bernoulli

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passed #962590
run_curve_fitting

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passed #962586
run_getting_started_1

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passed #962587
run_getting_started_2

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passed #962588
run_getting_started_3

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passed #962585
run_ipynb

00:01:28