message: Set frugal garbage collection policy on Bigtable
  Without this setting, the default is "never", which
  can cause clutter, particularly in
  `table_state=metadata:game_counter`.
diff: @@ -97,7 +97,9 @@ function create_cbt_table() {
  ${CBT_INSTANCE}-c ${CBT_ZONE} 3 SSD && \
  cbt -project ${PROJECT} -instance ${CBT_INSTANCE} createtable ${CBT_TABLE} && \
  cbt -project ${PROJECT} -instance ${CBT_INSTANCE} createfamily ${CBT_TABLE} tfexample && \
  - cbt -project ${PROJECT} -instance ${CBT_INSTANCE} createfamily ${CBT_TABLE} metadata ); then
  + cbt -project ${PROJECT} -instance ${CBT_INSTANCE} setgcpolicy ${CBT_TABLE} tfexample maxversions=1 &&
  + cbt -project ${PROJECT} -instance ${CBT_INSTANCE} createfamily ${CBT_TABLE} metadata && \
  + cbt -project ${PROJECT} -instance ${CBT_INSTANCE} setgcpolicy ${CBT_TABLE} metadata maxversions=1 ); then
  echo "Could not create table ${CBT_TABLE} on instance ${CBT_INSTANCE} in project ${PROJECT}"
  return 1
  fi
  