Remove double comparing of content out of the DefaultHttp2GoAwayFrame…

….equals()

Motivation:
In `DefaultHttp2GoAwayFrame.equals()` a content compared twice: explicitly and in the `super` method.

Modifications:
Remove explicit content comparision.
Make `hashCode()` consistent with `equals()`.

Result:
A `DefaultHttp2GoAwayFrame.equals()` work faster.

codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2GoAwayFrame.java

@@ -160,15 +160,13 @@ public boolean equals(Object o) {
             return false;
         }
         DefaultHttp2GoAwayFrame other = (DefaultHttp2GoAwayFrame) o;
-        return super.equals(o) && errorCode == other.errorCode && content().equals(other.content())
-            && extraStreamIds == other.extraStreamIds;
+        return errorCode == other.errorCode && extraStreamIds == other.extraStreamIds && super.equals(other);
     }
 
     @Override
     public int hashCode() {
-        int hash = 237395317;
+        int hash = super.hashCode();
         hash = hash * 31 + (int) (errorCode ^ (errorCode >>> 32));
-        hash = hash * 31 + content().hashCode();
         hash = hash * 31 + extraStreamIds;
         return hash;
     }