add more tests for KVM and fix them

See merge request !752

fixes 794185d0

Otherwise it's installed by python setup.py outside of buildout

This is partially WIP but I let @jerome, @Nicolas and @tomo to review it. 

Thie WIP is resilient tests included on it, it may cause the test runs for several hours.

My current idea is release all except resilient one, them use the Test case as a Library and recreate additional folders/softwares, which will run resilient tests. 

It still required to see if we can optimise the compilation maximazing the use of shared.

See merge request !748

This MR is a complement of nexedi/slapos.core!214, however it can be merged before the release of slapos.core because it won't be used until slapos.toolbox (actuall runner code) is changed to call them.

/cc @jerome @tomo @Nicolas

See merge request !751

This reverts commit de1e9ea0.

2.7.1+slapos006 revealed a bug in buildout bug, breaking resilient KVM.

Commit f355e0af didn't work because
GCC building ignores LDFLAGS when linking libgfortran.so
whereas the latter does not even need zlib and would be linked to
system zlib (if it exists) for nothing.

In our case, there seems to be no zlib code inside the installed files.

  This allow slaprunner call the API more easily.

  This may include basic usage of webrunner and as well basic
  resilience takeover.

The only change should be the upgrade of rdiff-backup
(from 1.0.5+SlapOSPatched001 to 1.3.4nxd6-SlapOSPatched001)
for some SR that extend the resilient stack.

For some SR, it implies the following upgrades:
- decorator: 4.3.0
- gitdb2: 2.0.5
- smmap2: 2.0.5
- subprocess32: 3.5.3

As https-only becomes default, tests are adapted in order to follow new
approach, case by case, or the redirect http->https is asserted, or https
access is used instead of http.

This is required for Python 3.7

- move or link instead of copying
- don't set too open permissions

See merge request !747

   This would allow the webrunner invoke it to bootstrap the instance
   rather them create the folders manually.

  Creating this file and updating the slapos.cfg configuration
  is possible to call slapos node format from the partition in the
  same way you would do in a computer.