Also, allows providing mroonga with a different soname.

A better implementation would be at libslap level (so that it works for
slapconsole too, for example), but requires too ugly hacks to accomodate
current data structure compared to change's otherwise (lack of) complexity.

It was reintroduced by a nightmarish merge: 42cfacae .

(cherry picked from commit 13fce878)

Conflicts:
	stack/slapos.cfg

(cherry picked from commit d666f259)

setup.py has been sorted alphabetically prior the merge.

Conflicts:
	component/slapos/buildout.cfg
	setup.py
	stack/slapos.cfg

This was intended in 795cedcf, but it should not be needed to revert there.

In preparation for better ERP5 clusterisation.

Based on work by Romain Courteaud <romain@nexedi.com>.

In preparation for better ERP5 clusterisation.

This reverts commit fdb2b87b.
This breaks erp5 test runner (maybe it does not accept IPv6 in SQL
connection strings).