People who invest in companies that frack are people who have an interest in the success of the companies who frack - most likely proportional to the amount of their investment.
I guess some of those $27 donations Bernie's been getting could be from people who invest in tracking companies. I don't think that's anything like the money that HRC is getting from investors at her corporate fund raisers. So, no, no hypocrisy on Bernie's part.
If you want the best argument against frackers influencing HRC, it's that energy doesn't even crack the top 20 in terms of which industrial segments are the biggest contributors to her campaign.