Previously it was required to put \ into multi-entry gowork.install,
because the way it was processed was to directly pass it into bash
command, and if \n were there the command was cut by bash and the
trailing was considered as another command.

We can avoid that by explicitly processing \n in gowork.install and
translate it to just ' '. This helps people because now gowork.install
becomes just a regular multiline buildout entry, similar e.g. to
gowork.cpkgpath et all.

Here is one example where it helps:

jerome/slapos@95c45fe0 (comment 68408)

/reviewed-by @jerome
/reviewed-on nexedi/slapos!430

Since f427842b some software releases has been
found to be without pinnsed eggs for GitPython dependency.

/reviewed-on !432

/reviewed-on nexedi/slapos!427

/reviewed-on !413

using husky + lint-staged

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 nexedi/slapos!409

/reviewed-on nexedi/slapos!411

/reviewed-on !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 nexedi/slapos!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'