add retry and proxywrite for debian family OSes

[Dan33l]

Fixes #252

It looks that it is missing retry entry only in template of Debian family OSes. It is already present in others families.

It looks that it is missing proxy_write entry in RedHat and Debian OSes.
Accordingly with proxy_write_maps it looks that it should be present also in CentOS7 at least. But to be preservative, i only added it in Debian family.

[Dan33l]

It looks that camptocamp/augeas have dependencies puppetlabs/stdlib (>= 3.2.0 < 6.0.0). But during acceptance puppetlabs/stdlib 6.0.0 is installed and so can not install camptocamp/augeas.

I am surprised that PR #246 had used puppetlabs-stdlib (v5.2.0)
https://travis-ci.org/camptocamp/puppet-postfix/jobs/529839716#L1081

[Dan33l]

@mcanevet @raphink can we use puppetlabs/stdlib 6.0.0 with camptocamp/augeas ?

If yes i'll propose a PR to modify camptocamp/augeas metadata.

[raphink]

Sure version 6.0.0 should work

[Dan33l]

stdlib dependency looks to be removed:
voxpupuli/puppet-augeas#73

A new release of the camptocamp/augeas should be enough.

[raphink]

puppet-augeas 1.8.0 released

[Dan33l]

puppet-augeas 1.8.0 released

Nice. I restart the CI with a Close/Open of this PR.

[raphink]

(or you could have asked me and I would have restarted the build 😉 )

[Dan33l]

(or you could have asked me and I would have restarted the build wink )

I didn't want to disturb you. This way I was autonomous.

The PR should be ready for a review

[Dan33l]

thank you

[kenyon]

This actually fixes #204.