Remove sysvinit else clauses in NFS for Arch Linux

Currently the code tries to detect if Arch uses systemd via checking
comm= of PID 1. As access to proc filesystem might be restricted due to
hideproc set and systemd is default for all Arch Linux installations
since October 2012, let's just ditch that check.

plugins/hosts/arch/cap/nfs.rb

@@ -3,31 +3,15 @@ module VagrantPlugins
     module Cap
       class NFS
         def self.nfs_check_command(env)
-          if systemd?
-            return "/usr/sbin/systemctl status --no-pager nfs-server.service"
-          else
-            return "/etc/rc.d/nfs-server status"
-          end
+          return "/usr/sbin/systemctl status --no-pager nfs-server.service"
         end
 
         def self.nfs_start_command(env)
-          if systemd?
-            return "/usr/sbin/systemctl start nfs-server.service"
-          else
-            return "sh -c 'for s in {rpcbind,nfs-common,nfs-server}; do /etc/rc.d/$s start; done'"
-          end
+          return "/usr/sbin/systemctl start nfs-server.service"
         end
 
         def self.nfs_installed(environment)
-          Kernel.system("grep -Fq nfs /proc/filesystems")
-        end
-
-        protected
-
-        # This tests to see if systemd is used on the system. This is used
-        # in newer versions of Arch, and requires a change in behavior.
-        def self.systemd?
-          `ps -o comm= 1`.chomp == 'systemd'
+          Kernel.system("grep -Fq nfsd /proc/filesystems")
         end
       end
     end