`make perf' failed with perf 3.2

[lht]

All perf tests failed with perf 3.2. Printout looks like:

test [run-pass] ../src/test/bench/99bob-iter.rs ... 
error: test run failed!
command: /usr/bin/perf stat -r 3 x86_64-unknown-linux-gnu/test/perf/99bob-iter.stage2-x86_64-unknown-linux-gnu
stdout:
------------------------------------------

------------------------------------------
stderr:
------------------------------------------
Failed opening logfd: Invalid argument

------------------------------------------

rust: upcall fail 'explicit failure', ../src/compiletest/runtest.rs:455
FAILED
test [run-pass] ../src/test/bench/99bob-pattern.rs ... 
error: test run failed!
command: /usr/bin/perf stat -r 3 x86_64-unknown-linux-gnu/test/perf/99bob-pattern.stage2-x86_64-unknown-linux-gnu
stdout:
------------------------------------------

------------------------------------------
stderr:
------------------------------------------
Failed opening logfd: Invalid argument

[lht]

Fixed in ef0775f