doc: update BUGS.md.

doc/BUGS.md

@@ -19,13 +19,17 @@ Information that may be relevant, depending on the nature of your issue:
 * GPUs used (`sgminer --ndevs`);
 * whether you're using a pre-compiled binary or built from source;
 * `sgminer` version (`sgminer --version` and/or `git describe`);
-* contents of the configuration file;
+* contents of the configuration file and pool connection info;
 * launch procedure (manual or via script);
 * steps to repeat;
 * expected result;
 * actual result;
 * debug output (`sgminer --text-only --debug --verbose`).
 
+Be careful when posting the contents of your configuration file: although
+pool connection and protocol information is relevant in a certain sub-class
+of issues, login credentials (username and password) are most often not.
+
 If there is a need to provide more than a screenfull of log
 data, it is preferred that a link is given instead. Try
 [gist](https://gist.github.com).