For unknown reasons, this is now necessary

Otherwise, the sub-projects have both hostlabels as constraints. Was not
enforced like this before 2021-10-29. But now something triggered this,
possibly it was always ment to be like this? Only thing that happened
today was an OOM initiated kill of bs_sched on obs-backend, that maybe
re-read information that was stale for a long time.

Oh well...

mpcdf_setup_software_project.py

@@ -47,7 +47,9 @@ def do_mpcdf_setup_software_project(self, subcmd, opts, *args):
     prjconf_tail = "".join(prjconf[end + 1:])
     prjconf = [start_marker]
 
+    prjconf.append('%if "%_project" == "software"')
     prjconf.append("Constraint: hostlabel sandybridge")
+    prjconf.append("%endif")
     prjconf.append("")
     prjconf.append(r"PublishFilter: ^.*\.src\.rpm$")
     prjconf.append("")