resilient: export script should try several times before definitely failing

The more there is data to backup, the more likely something can go wrong.
Running the exporter script several times will copy less and less things
at each run, so it should increase the probability to succeed.

stack/resilient/buildout.cfg

@@ -59,7 +59,7 @@ mode = 0644
 recipe = slapos.recipe.template
 url = ${:_profile_base_location_}/pbsready-export.cfg.in
 output = ${buildout:directory}/pbsready-export.cfg
-md5sum = 031fb7785cd5e99c2d794fa7e00e5190
+md5sum = 793f1843a643b3c91b658eca2bad5abc
 mode = 0644
 
 [template-pull-backup]

stack/resilient/pbsready-export.cfg.in

@@ -57,6 +57,7 @@ executable = $${exporter:wrapper}
 wrapper = $${rootdirectory:bin}/exporter
 notify = $${slap-parameter:notify}
 pidfile = $${resilient-directory:pid}/$${:name}.pid
+max-run = 3
 
 [notifier-exporter-promise]
 recipe = slapos.recipe.template:jinja2