riemann-health service: add procps to path (#19237)

Changed files
+1
nixos
modules
services
monitoring
+1
nixos/modules/services/monitoring/riemann-tools.nix
···
systemd.services.riemann-health = {
wantedBy = [ "multi-user.target" ];
+
path = [ procps ];
serviceConfig = {
User = "riemanntools";
ExecStart = "${healthLauncher}/bin/riemann-health";