[CE-187] Pull ARCH relevant docker images

`make setup-worker` pulls x86_64 docker images on
non x86_64 platform. This PR ensures that architecture
relevant docker images are pulled instead.

Change-Id: Ib03dd72001e2a913c337dfb1711683dc5c152272
Signed-off-by: Krishna Harsha Voora <krishvoor@in.ibm.com>

scripts/worker_node/download_images.sh

@@ -13,7 +13,7 @@ else
 fi
 
 # pull fabric images
-ARCH=x86_64
+ARCH=`uname -m | sed 's|i686|x86|' | sed 's|x86_64|x64|'`
 BASEIMAGE_RELEASE=0.3.1
 BASE_VERSION=1.0.0
 PROJECT_VERSION=1.0.0