[python3-ldap] Socket errors carried through

[Joseph L. Casale]

> This means that the server is not sending an unsolicited Message.
> When you get this exception? While sending or receiving?

On the outbound search request, I couldn't tell you without patching
the library and adding log statements.

I did notice something rather wasteful though, I make several search
attempts separated by a short bit of logic and each of those leverages
a context manager with the connection and given the connection is
not instantiated and opened/bound its cycling servers or each search.

Not really efficient. I am going to open the connection before I pass it
along, it should cycle through to the first available server at that time
and maintain a known working connection for the next minute while
I make a few searches.

Thanks,
jlc