borken pipe on jenkins

Now I've actually added some monitoring on all opened and closed sockets in the python tests, and it turns out the recent patch had no effect because the tearDown() is overloaded in TestVTYBase. With every running test, another socket is opened and they aren't closed until presumably the test py program exits. "40 sockets open", "41 sockets open", "42 sockets open", ... Found two places where we need to close sockets, and now the number of open sockets stays between 0 and 1. Patches are https://gerrit.osmocom.org/1903 https://gerrit.osmocom.org/1905 Will update the docker for openbsc tests when it's merged, and hopefully we can remove the extra monitoring of tcp sockets soon. ~N