Fixed bug in build container build script

docker/buildcontainer/build_circle.sh

@@ -8,7 +8,7 @@ if [[ -e ~/docker/centos.tar ]]; then
   docker load -i ~/docker/centos.tar;
 else
   docker build --tag "grafana/buildcontainer" docker/buildcontainer
-  docker save grafana:buildcontainer > ~/docker/centos.tar;
+  docker save grafana/buildcontainer > ~/docker/centos.tar;
 fi