Fixes in `condenser_get_followers`, `condenser_get_following` SQL functions

hive/db/sql_scripts/condenser_follows.sql

@@ -27,7 +27,7 @@ BEGIN
   __account_id = find_account_id( _account, True );
   __start_id = find_account_id( _start, _start <> '' );
   IF __start_id <> 0 THEN
-      SELECT INTO __start_id COALESCE( ( SELECT id FROM hive_follows WHERE following = __account_id AND follower = __start_id ), 0 );
+      SELECT INTO __start_id ( SELECT id FROM hive_follows WHERE following = __account_id AND follower = __start_id );
   END IF;
   RETURN QUERY SELECT
      ha.name
@@ -55,7 +55,7 @@ BEGIN
   __account_id = find_account_id( _account, True );
   __start_id = find_account_id( _start, _start <> '' );
   IF __start_id <> 0 THEN
-      SELECT INTO __start_id COALESCE( ( SELECT id FROM hive_follows WHERE follower = __account_id AND following = __start_id ), 0 );
+      SELECT INTO __start_id ( SELECT id FROM hive_follows WHERE follower = __account_id AND following = __start_id );
   END IF;
   RETURN QUERY SELECT
      ha.name

tests_api @ f93c1be9

-Subproject commit fba171b01622cae77e8b6d9f7f5be3c14f920924
+Subproject commit f93c1be91226f54b8b389d69195ca4e7cde1a851