Samba admin user dropdown shows only first page of system users

@suman

only the first page displayed at the users page gets selectable in the admin user dropdown menu in samba exports, in my case a user smbuser1 is selectable as it is listed on the first page, another user smbadmin isnt as its on the second page

Thanks for reporting this @felixbrucker. I have fixed it in this commit. It should be merged into 3.8-5