Correct unit on the Y axis for Zookeeper watch count

Fixes PROD-34649

Change-Id: I949e8d4956e7241fc0c691f6c6528709a15a40b2
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index a600206..8e70bed 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -38,6 +38,7 @@
     virtualenv $VENV_DIR
     source ${VENV_DIR}/bin/activate
     python -m pip install salt${PIP_SALT_VERSION}
+    python -m pip install 'msgpack<1.0.0'
 }
 
 setup_pillar() {