openvswitch fails to build in xenial on armhf

[Matthias Klose]

openvswitch fails to build in xenial on armhf, using ppa:ubuntu-toolchain-r/ppa

see https://launchpad.net/ubuntu/+archive/test-rebuild-20160614/+build/9982296
https://launchpadlibrarian.net/265430225/buildlog_ubuntu-xenial-armhf.openvswitch_2.5.0-0ubuntu1_BUILDING.txt.gz

## ------------- ##
## Test results. ##
## ------------- ##

ERROR: 1731 tests were run,
3 failed unexpectedly.
1 test was skipped.
## -------------------------- ##
## testsuite.log was created. ##
## -------------------------- ##

Please send `tests/testsuite.log' and all information you think might help:

   To: <email address hidden>
   Subject: [openvswitch 2.5.0] testsuite: 889 951 1717 failed

You may investigate any problem if you feel able to do so, in which
case the test suite provides a good starting point. Its output may
be found below `tests/testsuite.dir'.

make[5]: *** [check-local] Error 1