message: [mint] Fix docker mint config reference
  Closes:
  Approved by: davidiw
diff: set -ex
  export RUST_BACKTRACE=full
  -/opt/libra/bin/faucet-config-builder \
  +/opt/libra/bin/config-builder faucet \
  -o /opt/libra/etc \
  - -n $CFG_NUM_VALIDATORS \
  -s $CFG_SEED
  cd /opt/libra/bin && \
  