Fix off-by-one error in schannel's max_protocol_version

Author: blyxxyz

src/imp/schannel.rs

@@ -22,7 +22,7 @@ static PROTOCOLS: &'static [Protocol] = &[
 
 fn convert_protocols(min: Option<::Protocol>, max: Option<::Protocol>) -> &'static [Protocol] {
     let mut protocols = PROTOCOLS;
-    if let Some(p) = max.and_then(|max| protocols.get(..max as usize)) {
+    if let Some(p) = max.and_then(|max| protocols.get(..=max as usize)) {
         protocols = p;
     }
     if let Some(p) = min.and_then(|min| protocols.get(min as usize..)) {

src/test.rs

@@ -261,6 +261,7 @@ fn server_no_shared_protocol() {
     let socket = p!(TcpStream::connect(("localhost", port)));
     let builder = p!(TlsConnector::builder()
         .add_root_certificate(root_ca)
+        .min_protocol_version(Some(Protocol::Tlsv11))
         .max_protocol_version(Some(Protocol::Tlsv11))
         .build());
     assert!(builder.connect("localhost", socket).is_err());