Specifying cython version to use

Change-Id: I6c0f03e582c33c57b5a6c7fe5f46429e010dd259
diff --git a/Dockerfile.base.alpine b/Dockerfile.base.alpine
index da1d7ae..ac1d93c 100644
--- a/Dockerfile.base.alpine
+++ b/Dockerfile.base.alpine
@@ -29,7 +29,7 @@
 
 # Install app dependencies
 RUN apk add build-base gcc abuild binutils python-dev libffi-dev openssl-dev git linux-headers && \
-    pip install cython enum34 six && \
+    pip install cython==0.24.1 enum34 six && \
     pip install -r /tmp/requirements.txt && \
     apk del --purge build-base gcc abuild binutils python-dev libffi-dev openssl-dev git linux-headers