message: [tf] fix variable name for structure log
  Closes:
  Approved by: rustielin
diff: {"name": "CFG_NUM_VALIDATORS_IN_GENESIS", "value": "${cfg_num_validators_in_genesis}"},
  {"name": "CFG_SEED", "value": "${cfg_seed}"},
  {"name": "CFG_SEED_PEER_IP", "value": "${cfg_seed_peer_ip}"},
  - %{ if slog_path != "" }
  + %{ if structlog_path != "" }
  {"name": "STRUCT_LOG_FILE", "value": "${structlog_path}"},
  %{ endif }
  {"name": "RUST_LOG", "value": "${log_level}"}
  