fix duplicate docker builds

docker/build_docker.sh

@@ -5,18 +5,14 @@ set -u
 BUILD_NAME=0.5.1
 
 for type in pyston pyston-numpy; do
-    for tag in latest ${BUILD_NAME}; do
     cd ~/pyston/docker/${type}
     # "docker build" only recently gained the ability to take multiple -t flags
     docker build -t pyston/${type}:latest ~/pyston/docker/${type}
     docker build -t pyston/${type}:${BUILD_NAME} ~/pyston/docker/${type}
-    done
 done
 
 for type in pyston pyston-numpy; do
-    for tag in latest ${BUILD_NAME}; do
     cd ~/pyston/docker/${type}
     docker push pyston/${type}:latest
     docker push pyston/${type}:${BUILD_NAME}
-    done
 done