Don't modify members of new_resource in pw group implmentationjdm/freebsd-pw-fix

This was causing the

```
Chef::Resource::Group
  group modify action
    when there is a group
      behaves like correct group management
        when the users exist
          when append is not set
            when group already contains some users
              should remove all existing users and only add the new users to the group
```
spec to fail. The test passes an array which gets modified which breaks the test.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/chef/provider/group/pw.rb b/lib/chef/provider/group/pw.rb
index f877ed2424..5b5c8136f1 100644
--- a/lib/chef/provider/group/pw.rb
+++ b/lib/chef/provider/group/pw.rb
@@ -109,7 +109,7 @@ class Chef
           else
             # Append is not set so we're resetting the membership of
             # the group to the given members.
-            members_to_be_added = @new_resource.members
+            members_to_be_added = @new_resource.members.dup
             @current_resource.members.each do |member|
               # No need to re-add a member if it's present in the new
               # list of members