Remove libxml2-devel from list of Fedora/RHEL dependencies.
Remove libxml2-devel from list of Fedora/RHEL dependencies.

ranjan1990/mlpack,ranjan1990/mlpack,palashahuja/mlpack,palashahuja/mlpack,ajjl/mlpack,darcyliu/mlpack,palashahuja/mlpack,darcyliu/mlpack,ajjl/mlpack,ranjan1990/mlpack,darcyliu/mlpack,ajjl/mlpack