Fix assertion in NullSecurityContextRepository

Issue gh-11060

web/src/main/java/org/springframework/security/web/context/NullSecurityContextRepository.java

@@ -53,9 +53,9 @@ public final class NullSecurityContextRepository implements SecurityContextRepos
 	 *
 	 * @since 5.8
 	 */
-	public void setSecurityContextHolderStrategy(SecurityContextHolderStrategy strategy) {
-		Assert.notNull(this.securityContextHolderStrategy, "securityContextHolderStrategy cannot be null");
-		this.securityContextHolderStrategy = strategy;
+	public void setSecurityContextHolderStrategy(SecurityContextHolderStrategy securityContextHolderStrategy) {
+		Assert.notNull(securityContextHolderStrategy, "securityContextHolderStrategy cannot be null");
+		this.securityContextHolderStrategy = securityContextHolderStrategy;
 	}
 
 }