package/collectd: keep postgresql_default.conf when needed

$(TARGET_DIR)/usr/share/collectd/postgresql_default.conf
should not be removed when postgresql support is enabled,
as that module tries to load that file by default.

Signed-off-by: Pascal de Bruijn <p.debruijn@unilogic.nl>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 35e845700fb15b4ab30678c073300b508db4eb95)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/collectd/collectd.mk

@@ -198,8 +198,14 @@ endif
 define COLLECTD_INSTALL_TARGET_CMDS
 	$(TARGET_MAKE_ENV) $(MAKE) DESTDIR=$(TARGET_DIR) -C $(@D) install
 	rm -f $(TARGET_DIR)/usr/bin/collectd-nagios
+endef
+
+ifeq ($(BR2_PACKAGE_COLLECTD_POSTGRESQL),)
+define COLLECTD_REMOVE_UNNEEDED_POSTGRESQL_DEFAULT_CONF
 	rm -f $(TARGET_DIR)/usr/share/collectd/postgresql_default.conf
 endef
+COLLECTD_POST_INSTALL_TARGET_HOOKS += COLLECTD_REMOVE_UNNEEDED_POSTGRESQL_DEFAULT_CONF
+endif
 
 define COLLECTD_INSTALL_INIT_SYSTEMD
 	$(INSTALL) -D -m 644 package/collectd/collectd.service \