Additional speculative fix for SL-15547: Viewer hung while looking for a file...

Additional speculative fix for SL-15547: Viewer hung while looking for a file in the cache. I am still unable to reproduce this problem, although others have so I am trying a more aggressive approach for them to test.  I tried this as part of last speculative fix but saw what I thought were scary side effects in the log/console.  Turns out, those are there in the release viewer so probably unrelated to this change.

indra/llfilesystem/llfilesystem.cpp

@@ -164,6 +164,10 @@ BOOL LLFileSystem::read(U8* buffer, S32 bytes)
             success = FALSE;
         }
     }
+    else
+    {
+        success = FALSE;
+    }
 
     if (success == TRUE)
     {