fixes an issue with deleting bgp neighbors.
fixes an issue with deleting bgp neighbors.

This commit addresses a problem with deletting neighbors due to command syntax
diffferences.  The delete method will now check if the neighbor was deleted
and if not, try to delete it as a peer-group

mzbenami/pyeapi,mitchmahan/pyeapi,arista-eosplus/pyeapi,jerearista/pyeapi,devtodor/pyeapi-py3,SivagnanamCiena/pyeapi