MemoryPressureMesosTest.CGROUPS_ROOT_Statistics and CGROUPS_ROOT_SlaveRecovery are flaky

PERFORMED MAKE CHECK NODE-001
[ RUN      ] MemoryPressureMesosTest.CGROUPS_ROOT_Statistics
I1005 14:37:35.585067 38479 exec.cpp:133] Version: 0.24.0
I1005 14:37:35.593789 38497 exec.cpp:207] Executor registered on slave 20151005-143735-2393768202-35106-27900-S0
Registered executor on svdidac038.techlabs.accenture.com
Starting task 010b2fe9-4eac-4136-8a8a-6ce7665488b0
Forked command at 38510
sh -c 'while true; do dd count=512 bs=1M if=/dev/zero of=./temp; done'


PERFORMED MAKE CHECK NODE-002
[ RUN      ] MemoryPressureMesosTest.CGROUPS_ROOT_Statistics
I1005 14:38:58.794112 36997 exec.cpp:133] Version: 0.24.0
I1005 14:38:58.802851 37022 exec.cpp:207] Executor registered on slave 20151005-143857-2360213770-50427-26325-S0
Registered executor on svdidac039.techlabs.accenture.com
Starting task 9bb317ba-41cb-44a4-b507-d1c85ceabc28
sh -c 'while true; do dd count=512 bs=1M if=/dev/zero of=./temp; done'
Forked command at 37028
../../src/tests/containerizer/memory_pressure_tests.cpp:145: Failure
Expected: (usage.get().mem_medium_pressure_counter()) >= (usage.get().mem_critical_pressure_counter()), actual: 5 vs 6
2015-10-05 14:39:00,130:26325(0x2af08cc78700):ZOO_ERROR@handle_socket_error_msg@1697: Socket [127.0.0.1:37198] zk retcode=-4, errno=111(Connection refused): server refused to accept the client
[  FAILED  ] MemoryPressureMesosTest.CGROUPS_ROOT_Statistics (4303 ms)