Use a special milter to do what postfix cannot do with its internal
mechanisms.
- fixes postfix-generated bounces so they reach postmaster mail address
  without being rewritten
- actually makes postfix relay rewritten mails (virtual_alias implicitly
  affects virtual_domains, in turn making all mail addresses considered
  locally hosted, which cannot and must not successfully deliver)
Also, backport a yet-unreleased-but-already-upstreamed patch fixing
rcpt value truncation, which breaks when recipient address is not
enclosed in angle brackets - making the mail still reach original
recipient.

Disable more mariadb options during backup restoration:
- relax durability
- disable binlogs
- disable slow log
Bits of this commit were already accidentally (but harmlessly) pushed as
part of
  commit 5bde847f
  Author: Vincent Pelletier <vincent@nexedi.com>
  Date:   Tue Feb 21 16:02:21 2017 +0900

    stack.erp5: Avoid duplicating mariadb service paths.

1.8.X is current stable series of Go.

https://golang.org/doc/go1.8
https://golang.org/doc/devel/release.html#go1.8

Besides many other significant improvements it should now also support ARM64.

/cc @jp
/reviewed-by TrustMe  (tested on helloworld)

Otherwise it started to fail this way:

[2017-02-22 11:49:22,982] INFO     --- FAIL: TestLoadFixed (0.00s)
[2017-02-22 11:49:22,982] INFO          time_test.go:929: Now().In(loc).Zone() = "-01", -3600, want "GMT+1", -3600
[2017-02-22 11:49:22,983] INFO     FAIL
[2017-02-22 11:49:22,983] INFO     FAIL time    2.380s

See https://github.com/golang/go/issues/16352#issuecomment-255835099 and around
for details.

This way, processing nodes are sorted the same way as the node ids, making
cross-referencing easier.

Prevents a few possible accidental variable expansions and space
susceptibilities.

This reverts commit eb6f94c1.