fix(Core/Spells): Spell ID Shadow Ward (Warlock) (#1971)

- Set correct ID of warlock spell Shadow Ward. It was set to -7235(Shadow Protection) which is wrong
- Correct spellID is 6229 (Shadow Ward)

data/sql/updates/pending_db_world/rev_1560493947655900000.sql

@@ -0,0 +1,3 @@
+INSERT INTO `version_db_world` (`sql_rev`) VALUES ('1560493947655900000');
+
+UPDATE `spell_script_names` SET `spell_id`=-6229 WHERE `ScriptName`='spell_warl_shadow_ward';