write_graphite: Use the complain mechanism to report connection errors.

Fixes Github issue #236. Thanks to @pyr for reporting it!
src/utils_complain.[ch]: Fix the complaint mechanism after the sub-second change.
write_graphite plugin: Remove two more redundant error messages.

The failing functions already print an error message; don't spam the logs
by duplicating this.

Further fixes Github issue #236.
src/utils_dns.c: Improve ordering of includes.

sys, followed by net, followed by netinet, followed by arpa
that should be the most logical order

Signed-off-by: Florian Forster <octo@collectd.org>
Fix make distcheck (against release 5.1.1)

Signed-off-by: Florian Forster <octo@collectd.org>
make distcheck : perllocal.pod was missing. Fixed

Signed-off-by: Florian Forster <octo@collectd.org>
bugfix ("cannot find collectd.h") for branch master (and 5.2)

Signed-off-by: Florian Forster <octo@collectd.org>
src/Makefile.am: Fix "make distcheck".

protoc-c has a weird handling of files not in the CWD: They have to be
specified with the "-I" option _and_ you need to specify the full path
to the file.
Added "tar-pax" (bugfix for long filenames with make distcheck)

Signed-off-by: Florian Forster <octo@collectd.org>
Bumped version to 5.1.2; Updated ChangeLog.
Merge branch 'collectd-5.1' into collectd-5.2

Conflicts:
	ChangeLog
	src/write_graphite.c
	version-gen.sh
Bumped version to 5.2.1; Updated ChangeLog.
Merge remote-tracking branch 'origin/collectd-5.2' into collectd-5.2
Updated ChangeLog.