maint: Suggest where to start troubleshooting SSL error message

Much like the infamous "hostname was not match" error message, there's
another SSL error that people run into that isn't clear how to
troubleshoot.

err: Could not send report: SSL_connect returned=1 errno=0
state=SSLv3 read server certificate B: certificate verify failed.

As far as I can tell this only ever happens when the clock is off on the
master or client. People seem to think it will happen other times, but
I haven't been able to reproduce it other ways - missing private key,
revoked cert, offline CA all have their own errors. I googled around
and the only thing I've seen for this error in relation to puppet is the
time sync problem.

So the error message text just has some additional info to suggest you
check your clocks.

Reviewed-by: Nick Lewis <nick@puppetlabs.com>