icinga2: Fix infinite loop regression

pkgs/servers/monitoring/icinga2/default.nix

···
 
     # Get rid of sbin
     sed -i 's/sbin/bin/g' $out/lib/icinga2/safe-reload
-    sed -i "2s:.*:ICINGA2_BIN=$out/bin/icinga2:" $out/bin/icinga2
     rm $out/sbin
 
     ${lib.optionalString withMysql ''