remove some keywoards from secp-sys Cargo.toml

Author: apoelstra

secp256k1-sys/Cargo.toml

@@ -9,7 +9,7 @@ homepage = "https://github.com/rust-bitcoin/rust-secp256k1/"
 repository = "https://github.com/rust-bitcoin/rust-secp256k1/"
 documentation = "https://docs.rs/secp256k1-sys/"
 description = "FFI for Pieter Wuille's `libsecp256k1` library."
-keywords = [ "crypto", "ECDSA", "secp256k1", "libsecp256k1", "bitcoin", "ffi" ]
+keywords = [ "secp256k1", "libsecp256k1", "ffi" ]
 readme = "README.md"
 build = "build.rs"
 links = "secp256k1"