[Discuss-gnuradio] Fix for coverity issues in adaptive filter

[Philip Balister]

Following up with Fridays question about the adaptive_filter* files in
gr_filter.

I couldn't find any real code that used it. So I prepared this patch to
remove the files. This resolves three coverity issues and removes what
looks like dead code.

The existing in tree adaptive filters do not use this code.

https://github.com/balister/GNU-Radio/tree/adap

Philip