[web test] silent 3.13 warning

[editcontrollers] Account for role in the ordering of entities (Complements #3031719) Only role='object' was correctly accounted for by 570208f74a84

[migration.sync_schema_props_perms] ensure all participants to a unique together constraint are there before adding CWUniqueConstraint. Closes #3038345

[session commit] save back exception context to avoid potentiel cluttering if some revert operation raise an exception

[pkg] python-central has been removed from Debian

[pkg] prepare 3.17.4

[pkg] merge centos 3.17.1-2 in stable (prepare 3.17.4)

Added tag cubicweb-centos-version-3.17.1-2 for changeset 965f894b63cb

[rqlrewrite] fix rqlrewrite unpredictability vs relation sharing. Closes #3036144 The relations index used to determine if relation may be shared only considered a single relation node per relation type. So when the same relation type occurs several time, dict order give unpredictable result. We shall properly consider all relations instead. Tentative test case included (but bug reproduction is by definition unpredictable...)

[rqlrewrite] rewrite doesn't need a solutions argument, always use the Select'ones Also, do a copy systematically else it may lead to empty solutions depending on the rewrite path. Test case tentative included in the following changeset.