Do a perfect match on the container name

This way we avoid to match every container that begins with the same
name.

plugins/named-containers/plugin.toml

@@ -1,4 +1,4 @@
 [plugin]
 description = "dokku core named containers plugin"
-version = "0.4.0"
+version = "0.4.0.1"
 [plugin.config]

plugins/named-containers/post-deploy

@@ -6,7 +6,7 @@ APP="$1"; APP_ROOT="$DOKKU_ROOT/$APP"
 for container in "$APP_ROOT"/CONTAINER.*; do
   DYNO=$(echo "$container" | sed -r 's/.*CONTAINER\.(.*)/\1/') || true
   NAME="$APP.$DYNO"
-  PREVIOUS=$(docker ps -a -q -f name="$NAME") || true
+  PREVIOUS=$(docker ps -a -q -f name="$NAME\$") || true
   if [[ -n $PREVIOUS ]]; then
     docker rename "$NAME" "$NAME.$(date +%s)" > /dev/null
   fi