Redmine #4312: Fix incorrect file location for backup repository.

Canonifying and appending the file name was done twice, so the fix
was simply to remove the first pass.
Print errno related string when SSL_read/write fail with SSL_ERROR_SYSCALL. Also moved a docstring to the proper place.
Changed wording to something nicer.
docstring fix.
SO_REUSEADDR missing is not a reason to WARN loudly. Demote to VERBOSE.
Demoted to VERBOSE the instructions on how to trust a new client.
Fix wording when trust fails, so that messages are not so aggressive.

Also Change wording in serverd messages from host to peer.
Merge pull request #1654 from kacfengine/repository_file_location

Redmine #4312: Fix incorrect file location for backup repository.
Amended @ediosyncratic's nitpicks.
Move new test into staging as long as it fails in build pipeline.

The test passes in a local run, so not reverting the change otherwise.
tests/unit: fix file_writer test on Mac OS X (Darwin) because of clang
Merge pull request #1659 from tzz/fix-darwin-unit-tests

tests/unit: fix file_writer test on Mac OS X (Darwin) because of clang
10_files/02_maintain/backup_repository.cf: try enabling again
Merge pull request #1660 from tzz/test/fix-backup-repository-test

10_files/02_maintain/backup_repository.cf: try enabling again
Fix /0 CIDR matching, it was triggerring undefined behaviour.
Update verify_users_pam.c

Updated for bug https://cfengine.com/dev/issues/5485 as requested by Volker Hilsheimer. 
This will allow compile on NetBSD.
Tested on NetBSD i386 version 6.1.3.
Merge pull request #1663 from fkruchio/master

Update verify_users_pam.c
Merge pull request #1658 from jimis/minor

Reduce and beautify messages related to TLS protocol and trust on keys.
Merge pull request #1661 from jimis/cidr_fix

CIDR fix for /0 in IPv4.
Redmine #5380: Introduce privilege elevation in Windows testing.

This is needed in order to run tests as a user other than
Administrator, even if that user has admin privileges. The reason is
that Windows by default runs every process with non-admin rights, so
we need to elevate the privileges ourselves.