some tests failed:
failure: http://buildbot.rust-lang.org/builders/auto-mac-64-opt/builds/2952
exception: http://buildbot.rust-lang.org/builders/auto-mac-32-opt/builds/2958
exception: http://buildbot.rust-lang.org/builders/auto-mac-64-nopt-t/builds/2953
exception: http://buildbot.rust-lang.org/builders/auto-linux-32-opt/builds/2944
exception: http://buildbot.rust-lang.org/builders/auto-linux-32-nopt-t/builds/2943
exception: http://buildbot.rust-lang.org/builders/auto-linux-64-opt/builds/2946
exception: http://buildbot.rust-lang.org/builders/auto-linux-64-nopt-t/builds/2939
exception: http://buildbot.rust-lang.org/builders/auto-linux-64-x-android-t/builds/2936
exception: http://buildbot.rust-lang.org/builders/auto-win-32-opt/builds/2611
exception: http://buildbot.rust-lang.org/builders/auto-win-32-nopt-t/builds/2608
exception: http://buildbot.rust-lang.org/builders/auto-win-64-opt/builds/1447
exception: http://buildbot.rust-lang.org/builders/auto-win-64-nopt-t/builds/1438