[Merge] ~paelzer/ubuntu/+source/openvswitch:avoid-runtime-dir-removal-lp-1910209 into ~ubuntu-server-dev/ubuntu/+source/openvswitch:master

[Christian Ehrhardt ]

Trivial fix to bug 1910209, but I'm unsure about potential unwanted implications (read: do you have anything this Dir NEEDS to be cleared for).

Up to your review and consideration.
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https://code.launchpad.net/~paelzer/ubuntu/+source/openvswitch/+git/openvswitch/+merge/395882
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