fix code style issues in circuit_breaker.cpp

src/brpc/circuit_breaker.cpp

@@ -155,14 +155,14 @@ bool CircuitBreaker::OnCallEnd(int error_code, int64_t latency) {
     if (_broken.load(butil::memory_order_relaxed)) {
         return false;
     }
-    if (!_long_window.OnCallEnd(error_code, latency) ||
-        !_short_window.OnCallEnd(error_code, latency)) {
+    if (_long_window.OnCallEnd(error_code, latency) &&
+        _short_window.OnCallEnd(error_code, latency)) {
+        return true;
+    }
     if (!_broken.exchange(true, butil::memory_order_acquire)) {
         UpdateIsolationDuration();
     }
     return false;
-    }
-    return true;
 }
 
 void CircuitBreaker::Reset() {