[DOCKER] get libdisni version from jar version

Automatically get libdisni version from DiSNI jar.
Before we had to manually update the DiSNI version
for building the native library on every release.

https://issues.apache.org/jira/projects/CRAIL/issues/CRAIL-100

Signed-off-by: Jonas Pfefferle <pepperjo@apache.org>
diff --git a/docker/RDMA/Dockerfile b/docker/RDMA/Dockerfile
index ab0bce9..52f7dd7 100644
--- a/docker/RDMA/Dockerfile
+++ b/docker/RDMA/Dockerfile
@@ -17,14 +17,14 @@
 FROM apache/incubator-crail:1.1
 MAINTAINER Apache Crail <dev@crail.apache.org>
 
-# TODO: automate update version
-ARG DISNI_COMMIT="v1.7"
-
 RUN echo "Crail-$LOG_COMMIT install rdma libraries and autotools" && \
     apt-get install -y --no-install-recommends \
     autoconf autotools-dev automake libtool make g++ \
     librdmacm-dev libibverbs-dev ibverbs-providers
 
+RUN echo "Retrieve DiSNI jar version to match native library build" && \
+    DISNI_COMMIT=v$(ls $CRAIL_HOME/jars/disni* | grep -oP "\d+\.\d+(?=\.jar$)")
+
 RUN echo "Crail-$LOG_COMMIT clone and build disni native library" && \
     cd && git clone https://github.com/zrlio/disni.git && \
     cd ~/disni/libdisni && \