testing: link in suricata-ffi, but don't use

Author: jasonish

rust/Cargo.lock.in

@@ -87,6 +87,7 @@ time = "=0.3.41"
 
 suricata-derive = { path = "./derive", version = "@PACKAGE_VERSION@" }
 suricata-sys = { path = "./sys", version = "@PACKAGE_VERSION@" }
+suricata-ffi = { path = "./ffi", version = "@PACKAGE_VERSION@" }
 
 suricata-lua-sys = { version = "5.4.8002" }