postgres: Merge upstream config WAL size changes

Signed-off-by: Florian Pritz <bluewind@xinu.at>

roles/postgres/templates/postgresql.conf.j2

@@ -210,8 +210,8 @@ dynamic_shared_memory_type = posix	# the default is the first option
 # - Checkpoints -
 
 #checkpoint_timeout = 5min		# range 30s-1d
-#max_wal_size = 1GB
-#min_wal_size = 80MB
+max_wal_size = 1GB
+min_wal_size = 80MB
 #checkpoint_completion_target = 0.5	# checkpoint target duration, 0.0 - 1.0
 #checkpoint_flush_after = 256kB		# measured in pages, 0 disables
 #checkpoint_warning = 30s		# 0 disables