Fix broken benchmarks

Author: elichai

.travis.yml

@@ -41,7 +41,7 @@ script:
   - cargo run --example sign_verify_recovery --features=recovery
   - cargo run --example generate_keys --features=rand
   - if [ ${TRAVIS_RUST_VERSION} == "stable" ]; then cargo doc --verbose --features="rand,serde,recovery,endomorphism"; fi
-  - if [ ${TRAVIS_RUST_VERSION} == "nightly" ]; then cargo test --verbose --benches --features=unstable; fi
+  - if [ ${TRAVIS_RUST_VERSION} == "nightly" ]; then cargo test --verbose --benches --features="unstable,recovery,rand"; fi
   - if [ ${TRAVIS_RUST_VERSION} == "nightly" -a "$TRAVIS_OS_NAME" = "linux" ]; then 
     cd no_std_test &&
     cargo run --release | grep -q "Verified Successfully";

src/ecdh.rs

@@ -304,7 +304,6 @@ mod benches {
         let s = Secp256k1::signing_only();
         let (sk, pk) = s.generate_keypair(&mut thread_rng());
 
-        let s = Secp256k1::new();
         bh.iter( || {
             let res = SharedSecret::new(&pk, &sk);
             black_box(res);

src/recovery.rs

@@ -363,6 +363,10 @@ mod tests {
 
 #[cfg(all(test, feature = "unstable"))]
 mod benches {
+    use rand::{thread_rng, RngCore};
+    use test::{Bencher, black_box};
+    use super::{Message, Secp256k1};
+
     #[bench]
     pub fn bench_recover(bh: &mut Bencher) {
         let s = Secp256k1::new();