Removed duplicate entry.
Merge pull request #2167 from schlamar/patch-1

provisioners/chef: removed duplicate entry.
Put nfs opts setup in separate function and configured to be called by both generic linux and arch nfs_options.  Fixes undefined method join exception in arch
Merge pull request #2176 from deltaroe/master

hosts/linux: put nfs opts setup in separate function
core: fix NoMethodError in Vagrant.has_plugin? [GH-1736]
Merge pull request #2189 from phinze/1736-fix-has-plugin-no-method-error

core: fix NoMethodError in Vagrant.has_plugin? [GH-1736]
Update issue reference on CHANGELOG
core: Allow strings to be used when checking for Guest capabilities