build: replace 'no_bssl' feature with 'boringssl-vendored'

The point of the feature is to build the vendored BoringSSL (i.e. we
would still use BoringSSL, just not build it), so this name makes more
sense.

Cargo.toml

@@ -20,10 +20,12 @@ exclude = [
 ]
 
 [features]
-no_bssl = []
+default = ["boringssl-vendored"]
+
+boringssl-vendored = []
 
 [package.metadata.docs.rs]
-features = ["no_bssl"]
+default-features = false
 
 [build-dependencies]
 cmake = "0.1"

src/build.rs

@@ -121,7 +121,7 @@ fn get_boringssl_cmake_config() -> cmake::Config {
 }
 
 fn main() {
-    if !cfg!(feature = "no_bssl") {
+    if cfg!(feature = "boringssl-vendored") {
         let bssl_dir = std::env::var("QUICHE_BSSL_PATH").unwrap_or_else(|_| {
             get_boringssl_cmake_config()
                 .build_target("bssl")