zlib: remove unnecessary else branch

PR-URL: https://github.com/nodejs/node/pull/17057
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/zlib.js

@@ -121,8 +121,7 @@ function zlibBufferSync(engine, buffer) {
   buffer = processChunkSync(engine, buffer, engine._finishFlushFlag);
   if (engine._info)
     return { buffer, engine };
-  else
-    return buffer;
+  return buffer;
 }
 
 function zlibOnError(message, errno) {