Remove `openssl-sys` as a dependency

`openssl-sys` isn't required anymore; it was added in the `ssl` branch
during the development phase.

Signed-off-by: Sayan Nandan <nandansayan@outlook.com>

Cargo.lock

@@ -726,7 +726,6 @@ dependencies = [
  "libtdb",
  "log",
  "openssl",
- "openssl-sys",
  "parking_lot",
  "regex",
  "serde",

server/Cargo.toml

@@ -25,7 +25,6 @@ regex = "1.4.3"
 tdb_macros = {path="../tdb-macros"}
 tokio-openssl = "0.6.1"
 openssl = { version = "0.10", features = ["vendored"] }
-openssl-sys = "0.9.60"
 [target.'cfg(not(target_env = "msvc"))'.dependencies]
 jemallocator = "0.3.2"