pinning cryptography package to avoid CryptographyDeprecationWarnings in tests

Change-Id: Ie934906836b18aaeacd61a40101311a073c12887
diff --git a/src/test/cord-api/setup_venv.sh b/src/test/cord-api/setup_venv.sh
index cf08442..da7e926 100755
--- a/src/test/cord-api/setup_venv.sh
+++ b/src/test/cord-api/setup_venv.sh
@@ -30,8 +30,8 @@
 echo "Installing python requirements in virtualenv with pip"
 source "${VENVDIR}/bin/activate"
 pip install --upgrade pip
-pip install robotframework robotframework-requests robotframework-sshlibrary pexpect  \
-    robotframework-httplibrary robotframework-kafkalibrary pygments pyyaml
+pip install cryptography==2.4.2 robotframework robotframework-requests robotframework-sshlibrary  \
+    pexpect robotframework-httplibrary robotframework-kafkalibrary pygments pyyaml
 pip install requests tinydb
 
 echo "CORD-TESTER virtualenv created. Run 'source ${VENVDIR}/bin/activate'."
\ No newline at end of file