There was two sections writing the file `bin/monitor-httpd` which led to some problems when running things

/reviewed-on nexedi/slapos!426

/reviewed-on !409

/reviewed-on !411

/reviewed-on nexedi/slapos!410

  Sticky computer on kvm cluster, will make the requester (root instance on this case), request
  the children on the same computer as itself.

/reviewed-on !421

usually, the software release path is :
in a web runner : /srv/slapgrid/slappartXX/srv/runner/project/buildout.cfg
in a test node : /srv/slapgrid/slappartX/srv/testnode/xx/inst/test0-XX/srv/runner/project/buldout.cfg

the previous regex was replacing in all slappartX and test0-X by the new test0-Y
which of course would make an existing path : /srv/slapgrid/test0-Y/.../test0-Y/...

This commit only replace the latest occurence in order to have
compatible code in the "normal" case, and in the test nodes

/reviewed-on nexedi/slapos!418

/reviewed-on nexedi/slapos!414

These are totally unrelated changes which were not meant to be pushed,
sorry.

Runner exporter failed with this message while checking if file changed during backup of instances files:

    < 3226bab4cd318d30cfbde18e6530435dcae3205f94103384ce266c3c73d1afeb  ./runner/instance/slappart2/srv/backup/pbs/slaprunner-slappart1-runner-1/backup.signature
    < 3226bab4cd318d30cfbde18e6530435dcae3205f94103384ce266c3c73d1afeb  ./runner/instance/slappart3/srv/backup/runner/backup.signature
    < 3226bab4cd318d30cfbde18e6530435dcae3205f94103384ce266c3c73d1afeb  ./runner/instance/slappart5/srv/backup/runner/backup.signature
    5248d5244
    < bb3d96876d1d6cecee9878d835e7515215fc5d2a6ae6b647d0e7915c36700b54  ./runner/instance/slappart4/srv/backup/runner/backup.signature
    ERROR: Some backups are not consistent, exporter should be re-run.

This is because instance in webrunner has also backup.signature the file is excluded while doing sha256sum on backup file:

    find -type f ! -name backup.signature -print0 | xargs -0 sha256sum | sort -k 66 > backup.signature

A fix is to exclude backup.signature in `find`.

If instance/slappartXX is not a folder but file, skip chdir else import/export fail with a message like:

    /srv/slapgrid/slappart18/bin/runner-exporter run at : Thu Oct  4 04:30:03 CEST 2018
    Traceback (most recent call last):
      File "<stdin>", line 17, in <module>
    OSError: [Errno 20] Not a directory: '/srv/slapgrid/slappart18/srv//runner/instance/slappart5-mariadb.dump.sql.gz'

This reverts commit 80673c8c.

All testnodes should have been updated by now, so this commit is no
longer needed.

/reviewed-on nexedi/slapos!419

/reviewed-on nexedi/slapos!416

/reviewed-on nexedi/slapos!415