[NUTCH-2786] add a warning for insecure TrustManager

[GraceXiaoYa]

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[lewismc]

@AthenaXiao thanks for the patch. I think it would be more appropriate to provide Javadoc. Can you consider this and resubmit your patch?

[lewismc]

@AthenaXiao I'm going to close this issue off. The Class is present in quite a few places within the Nutch source. It is named appropriately and really down to the consumer how they use it. Some Javadoc would be preferred. In the absence of that, this patch is not going to be merged in its current state. Thank you