Add option to force removing Dockerfile.stfubuntu

docker/build.sh

@@ -7,7 +7,7 @@ set -vx
 
 # Force removing stfubuntu docker image
 if [ "$1" == "--force-stfubuntu" ]; then
-    doker rmi `docker images -q stfubuntu` || exit 1
+    docker rmi `docker images -q stfubuntu` || exit 1
 fi
 # Check and build stfubuntu image
 if [ -z `docker images -q stfubuntu` ]; then