fix build on linux and darwin: missing openssl crate

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "ng-rocksdb"
 description = "Rust wrapper for Facebook's RocksDB embeddable database, fork for Nextgraph.org"
-version = "0.21.0-ngpreview.6"
+version = "0.21.0-ngpreview.7"
 edition = "2018"
 rust-version = "1.60"
 authors = ["Tyler Neely <t@jujit.su>", "David Greenberg <dsg123456789@gmail.com>"]
@@ -52,7 +52,7 @@ serde = { version = "1", features = [ "derive" ] }
 const-cstr = "0.3"
 uuid = { version = "1.0", features = ["v4"] }
 
-[target.'cfg(not(any(target_os = "linux",target_os = "darwin",target_os = "openbsd")))'.dependencies.openssl]
+[target.'cfg(not(any(target_os = "openbsd")))'.dependencies.openssl]
 version = "0.10"
 features = ["vendored"]