Debian: ${source:Version} dependency on python-openvswitch

As reported by lintian:

E: openvswitch source: not-binnmuable-any-depends-all openvswitch-ipsec -> python-openvswitch
N:
N:    The package is not safely binNMUable because an arch:any package depends
N:    on an arch:all package with a (= ${Source-Version}) or (=
N:    ${binary:Version}) relationship. Please use (= ${source:Version})
N:    instead.
N:
N:    Severity: important, Certainty: certain