add Group=netdata to systemd unit file (#19638)

* add Group=netdata to systemd unit file

* remove ExecStartPre

* rm mkdir /run/netdata

system/systemd/netdata.service.in

@@ -10,14 +10,13 @@ Wants=network-online.target nss-lookup.target
 LogNamespace=netdata
 Type=simple
 User=root
+Group=netdata
 RuntimeDirectory=netdata
 RuntimeDirectoryMode=0775
 PIDFile=/run/netdata/netdata.pid
 ExecStart=@sbindir_POST@/netdata -P /run/netdata/netdata.pid -D
 ExecStartPre=/bin/mkdir -p @localstatedir_POST@/cache/netdata
 ExecStartPre=/bin/chown -R @netdata_user_POST@ @localstatedir_POST@/cache/netdata
-ExecStartPre=/bin/mkdir -p /run/netdata
-ExecStartPre=/bin/chown -R @netdata_user_POST@ /run/netdata
 PermissionsStartOnly=true
 
 # saving a big db on slow disks may need some time

system/systemd/netdata.service.v235.in

@@ -10,6 +10,7 @@ Wants=network-online.target nss-lookup.target
 LogNamespace=netdata
 Type=simple
 User=root
+Group=netdata
 EnvironmentFile=-/etc/default/netdata
 ExecStart=@sbindir_POST@/netdata -D $EXTRA_OPTS