Merge pull request #2096 from liangxia/master

Update conditional expression to save steps

playbooks/byo/openshift-cluster/upgrades/docker/files/nuke_images.sh

@@ -1,22 +1,22 @@
 #!/bin/bash
 
 # Stop any running containers
-running_container_count=`docker ps -q | wc -l`
-if test $running_container_count -gt 0
+running_container_ids=`docker ps -q`
+if test -n "$running_container_ids"
 then
-    docker stop $(docker ps -q)
+    docker stop $running_container_ids
 fi
 
 # Delete all containers
-container_count=`docker ps -a -q | wc -l`
-if test $container_count -gt 0
+container_ids=`docker ps -a -q`
+if test -n "$container_ids"
 then
-    docker rm -f -v $(docker ps -a -q)
+    docker rm -f -v $container_ids
 fi
 
 # Delete all images (forcefully)
-image_count=`docker images -q | wc -l`
-if test $image_count -gt 0
+image_ids=`docker images -q`
+if test -n "$image_ids"
 then
     # Taken from: https://gist.github.com/brianclements/f72b2de8e307c7b56689#gistcomment-1443144
     docker rmi $(docker images | grep "$2/\|/$2 \| $2 \|$2 \|$2-\|$2_" | awk '{print $1 ":" $2}') 2>/dev/null || echo "No images matching \"$2\" left to purge."