OCP-DEMO Avoid error if a previous created image does not exist

  The script deletes the previous reference to the create docker image file but,
  before this commit, exit with an exception the first time the script is called.

Author: DavideD

openshift/message-board/script/install-custom-infinispan-image.sh

@@ -27,5 +27,5 @@ docker push ${IMAGE}
 
 # store the image reference to file
 # it will be used by the install-all script
-rm ./CUSTOM_INFINISPAN_IMAGE
-echo "$IMAGE" >> CUSTOM_INFINISPAN_IMAGE
+rm -fv ./CUSTOM_INFINISPAN_IMAGE
+echo "$IMAGE" >> CUSTOM_INFINISPAN_IMAGE