Core/Commands: .npc set faction fix and improvement (#1001)

Fix error message in console, and add help text for new 'npc set faction' command

data/sql/updates/pending_db_world/rev_1534115647861309430.sql

@@ -0,0 +1,12 @@
+INSERT INTO version_db_world (`sql_rev`) VALUES ('1534115647861309430');
+
+DELETE FROM `command` WHERE `name` IN
+('npc set factionid',
+'npc set faction temp',
+'npc set faction original',
+'npc set faction permanent');
+
+INSERT INTO `command` (`name`, `security`, `help`) VALUES
+('npc set faction temp', 3, 'Syntax: .npc set faction temp #factionid\r\n\r\nTemporarily set the faction of the selected creature to #factionid.'),
+('npc set faction original', 3, 'Syntax: .npc set faction original\r\n\r\nRevert the temporal faction of the selected creature.'),
+('npc set faction permanent', 3, 'Syntax: .npc set faction permanent #factionid\r\n\r\nPermanently set the faction of the selected creature to #factionid.');

src/server/scripts/Commands/cs_npc.cpp

@@ -133,9 +133,9 @@ public:
 
         static std::vector<ChatCommand> npcFactionCommandTable =
         {
-            { "Permanent",      SEC_ADMINISTRATOR,  false, &HandleNpcSetFactionIdCommand,      "" },
+            { "permanent",      SEC_ADMINISTRATOR,  false, &HandleNpcSetFactionIdCommand,      "" },
-            { "Temp",           SEC_ADMINISTRATOR,  false, &HandleNpcSetFactionTempIdCommand,  "" },
+            { "temp",           SEC_ADMINISTRATOR,  false, &HandleNpcSetFactionTempIdCommand,  "" },
-            { "Original",       SEC_ADMINISTRATOR,  false, &HandleNpcSetOriginalFaction,       "" }
+            { "original",       SEC_ADMINISTRATOR,  false, &HandleNpcSetOriginalFaction,       "" }
         };
 
         static std::vector<ChatCommand> npcSetCommandTable =