[Pkg-postgresql-public] Bug#823209: set dynamic_shared_memory_type from the new postgresql.conf

[Christoph Berg]

Package: postgresql-common
Version: 173
Severity: normal

Magnus just had the brilliant idea that the default for
dynamic_shared_memory_type in upgraded clusters shouldn't be "mmap",
but could just be grabbed from the initdb'ed new postgresql.conf that
we create anyway (but overwrite immediately). Let's implement that.

(And as a further idea, I would like to implement an option that would
use the new postgresql.conf and import the old settings, instead of
copying over the old file.)

Christoph