Bug#918273: eficas build depends on python-openturns that is currently not in buster

[Adrian Bunk]

Source: eficas
Version: 6.4.0-1-2
Severity: serious
Tags: ftbfs
Control: block -1 by 897768 902513

eficas build depends on python-openturns that is currently
not in buster due to #897768 and #902513.