Simplify the check for the xrss header

Signed-off-by: Matthew Arnold <[email protected]>

image-rs/src/signature/mechanism/simple/xrss.rs

@@ -106,10 +106,7 @@ impl RegistryClient {
             .await
             .context("Failed to query extensions supported by registry v2 endpoint")?;
 
-        let registry_signature_support_header = res.headers().get("x-registry-supports-signatures");
-        if registry_signature_support_header.is_some()
-            && registry_signature_support_header.unwrap() == "1"
-        {
+        if res.headers().get("x-registry-supports-signatures") == Some("1") {
             let oauth_token = self.get_oauth_token_for_registry(image, auth).await?;
             let res = self
                 .client
@@ -129,7 +126,7 @@ impl RegistryClient {
 
             for registry_signature in signatures_response_body.signatures.iter() {
                 let signature = base64::engine::general_purpose::STANDARD.decode(&registry_signature.content).context(
-                        "Error when decoding sognature from registry. Signature is not base64 encoded",
+                        "Error when decoding sognature from registry. Signature is not base64 encoded"
                 )?;
                 sigs.push(signature);
             }