Vendor curl-sys crate with patched curl

Summary:
Vendoring this patch: curl/curl#7737 to curl-sys rust crate. On windows the hg client is using curl that's bundled with sys-curl. I need this patch to have unix domain sockets working in hg client on windows.

I had to manually vendor https://raw.githubusercontent.com/mzr/curl/57e7ec4dbe4dd2831de51f2644879387d2ea7b44/docs/INSTALL because reindeer didn't do it. IDK why.

oss-eden-{darwin,linux,windows}-getdeps fail with:
```
FAILED: eden/scm/lib/backingstore/CMakeFiles/rust_backingstore.cargo eden/scm/lib/backingstore/debug/libbackingstore.a eden/scm/lib/backingstore/release/libbackingstore.a
cd /data/sandcastle/temp/fbcode_builder_getdeps/shipit/eden/eden/scm/lib/backingstore && /data/sandcastle/temp/fbcode_builder_getdeps/installed/cmake-hQhVzQT-WzFKTeqXjLxo5lLi8IG4_MjX2-YRqptCUVs/bin/cmake -E remove -f /data/sandcastle/temp/fbcode_builder_getdeps/shipit/eden/eden/scm/lib/backingstore/Cargo.lock && /data/sandcastle/temp/fbcode_builder_getdeps/installed/cmake-hQhVzQT-WzFKTeqXjLxo5lLi8IG4_MjX2-YRqptCUVs/bin/cmake -E env CARGO_TARGET_DIR=/data/sandcastle/temp/fbcode_builder_getdeps/build/eden/eden/scm/lib/backingstore CARGO_HOME=/data/sandcastle/temp/fbcode_builder_getdeps/build/eden/_cargo_home cargo build --release -p backingstore --features fb
    Blocking waiting for file lock on package cache
    Blocking waiting for file lock on package cache
error: failed to calculate checksum of: /data/sandcastle/boxes/eden-trunk-hg-fbcode-fbsource/third-party/rust/vendor/curl-sys-0.4.45+curl-7.78.0/curl/docs/INSTALL
Caused by:
  failed to open file `/data/sandcastle/boxes/eden-trunk-hg-fbcode-fbsource/third-party/rust/vendor/curl-sys-0.4.45+curl-7.78.0/curl/docs/INSTALL`
Caused by:
  No such file or directory (os error 2)
```

Not idea how to fix this. Seems related to the fact that reindeer didn't vendor docs/INSTALL.

# EDIT:
# It might been caused by some bug in hg. now it's fine
# The failure in oss-eden-linux-getdeps looks unrelated (something with rocksdb)

Reviewed By: krallin

Differential Revision: D31370778

fbshipit-source-id: a1245f8cb6b58f5765e34c95dfd78325a8e6e457

hphp/hack/src/facts/ffi_bridge/Cargo.toml

@@ -6,8 +6,6 @@ edition = "2018"
 
 [lib]
 path = "rust_facts_ffi_bridge.rs"
-test = false
-doctest = false
 crate-type = ["lib", "staticlib"]
 
 [dependencies]