doc: remove outdated try/catchstatements in sync

The code shows that it throws on a lack of entropy, but the note below says that it does not. Remove outdated `try/catch`statements in sync examples about crypto.randomBytes to make it clear
JungMinu · Sep 27, 2015 · Sep 27, 2015 · Sep 27, 2015 · Sep 27, 2015 · Sep 27, 2015
commit 69b5fb97f0856df35e5f49c62af4df6f788509df
diff --git a/doc/api/crypto.markdown b/doc/api/crypto.markdown
@@ -651,6 +651,7 @@ Generates cryptographically strong pseudo-random data. Usage:
     });
 
     // sync
+    // Implementation of handling erros is required.
     var buf = crypto.randomBytes(256);
     console.log('Have %d bytes of random data: %s', buf.length, buf);
-Original file line number
+Diff line change
@@ Expand Up @@
         });
         // sync
+        // Implementation of handling erros is required.
         var buf = crypto.randomBytes(256);
         console.log('Have %d bytes of random data: %s', buf.length, buf);
@@ Expand Down @@