message: [cluster-test]retry logic for failed query to prometheus
  Closes:
  Approved by: ankushagarwal
diff: @@ -6,6 +6,7 @@ use anyhow::{format_err, Result};
  use std::time::Duration;
  pub fn avg_txns_per_block(prometheus: &Prometheus, start: Duration, end: Duration) -> Result<f64> {
  + libra_retrier::retry(libra_retrier::fixed_retry_strategy(1_000, 5), || {
  prometheus
  .query_range_avg(
  "irate(libra_consensus_num_txns_per_block_sum[1m])/irate(libra_consensus_num_txns_per_block_count[1m])".to_string(),
  @@ -14,4 +15,5 @@ pub fn avg_txns_per_block(prometheus: &Prometheus, start: Duration, end: Duratio
  10, /* step */
  )
  .map_err(|e| format_err!("No txns_per_block data: {}", e))
  + })
  }
  