This closes #4311 when merged. Previously, once we hit the overload-queue-length, we'd be forever down over UDP from that point. Also adds new counter for overload drops & documents it.
fix distributor overload behaviour, closes #4311. Also adds & documen…
…ts metric overload-drops. Want to add a test too, not there yet.
fix up regression test that got confused by our new counter.
add a test for the overload limit in the distributor
make test a bit more robust against travis or slow servers
even longer timeout
improve query logging somewhat for bind backend
pipe timeout was equal to sleep(1) in the backend, leading to excessi…