`cargo run --bin tpch` fails with `thread 'main' panicked at 'Argument short must be unique -p is already in use'`

[alamb]

Describe the bug

When trying to run the tpch benchmarks (to validate #1291) a runtime error now results. I suspect validation has improved in clap. I could work around this and it is not blocking me

cd /data/arrow-datafusion && RUST_BACKTRACE=1 CARGO_TARGET_DIR=/data/target cargo run --bin  tpch -- --help
    Finished dev [unoptimized + debuginfo] target(s) in 0.11s
     Running `/data/target/debug/tpch --help`
thread 'main' panicked at 'Argument short must be unique

        -p is already in use', /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/clap-2.33.3/src/app/parser.rs:193:13
stack backtrace:
   0: rust_begin_unwind
             at /rustc/f1edd0429582dd29cccacaf50fd134b05593bd9c/library/std/src/panicking.rs:517:5
   1: std::panicking::begin_panic_fmt
             at /rustc/f1edd0429582dd29cccacaf50fd134b05593bd9c/library/std/src/panicking.rs:460:5
   2: clap::app::parser::Parser::debug_asserts
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/clap-2.33.3/src/app/parser.rs:193:13
   3: clap::app::parser::Parser::add_arg
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/clap-2.33.3/src/app/parser.rs:302:23
   4: clap::app::App::arg
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/clap-2.33.3/src/app/mod.rs:794:9
   5: <tpch::BallistaBenchmarkOpt as structopt::StructOptInternal>::augment_clap
             at ./benchmarks/src/bin/tpch.rs:64:17
   6: <tpch::BenchmarkSubCommandOpt as structopt::StructOptInternal>::augment_clap
             at ./benchmarks/src/bin/tpch.rs:171:23
   7: <tpch::TpchOpt as structopt::StructOptInternal>::augment_clap
             at ./benchmarks/src/bin/tpch.rs:179:15
   8: <tpch::TpchOpt as structopt::StructOpt>::clap
             at ./benchmarks/src/bin/tpch.rs:176:17
   9: structopt::StructOpt::from_args
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/structopt-0.3.25/src/lib.rs:1137:26
  10: tpch::main::{{closure}}
             at ./benchmarks/src/bin/tpch.rs:192:11
  11: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
             at /rustc/f1edd0429582dd29cccacaf50fd134b05593bd9c/library/core/src/future/mod.rs:80:19
  12: tokio::park::thread::CachedParkThread::block_on::{{closure}}
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.14.0/src/park/thread.rs:263:54
  13: tokio::coop::with_budget::{{closure}}
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.14.0/src/coop.rs:106:9
  14: std::thread::local::LocalKey<T>::try_with
             at /rustc/f1edd0429582dd29cccacaf50fd134b05593bd9c/library/std/src/thread/local.rs:399:16
  15: std::thread::local::LocalKey<T>::with
             at /rustc/f1edd0429582dd29cccacaf50fd134b05593bd9c/library/std/src/thread/local.rs:375:9
  16: tokio::coop::with_budget
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.14.0/src/coop.rs:99:5
  17: tokio::coop::budget
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.14.0/src/coop.rs:76:5
  18: tokio::park::thread::CachedParkThread::block_on
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.14.0/src/park/thread.rs:263:31
  19: tokio::runtime::enter::Enter::block_on
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.14.0/src/runtime/enter.rs:151:13
  20: tokio::runtime::thread_pool::ThreadPool::block_on
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.14.0/src/runtime/thread_pool/mod.rs:77:9
  21: tokio::runtime::Runtime::block_on
             at /home/alamb/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.14.0/src/runtime/mod.rs:463:43
  22: tpch::main
             at ./benchmarks/src/bin/tpch.rs:192:5
  23: core::ops::function::FnOnce::call_once
             at /rustc/f1edd0429582dd29cccacaf50fd134b05593bd9c/library/core/src/ops/function.rs:227:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

To Reproduce

# get latest dependent libraries
cargo update
# try and run tpch benchmark
cargo run --bin  tpch

Expected behavior
The benchmark program can run

Additional context
Add any other context about the problem here.