[Code Cleanup] Resharper Warnings (#2235)

* Remove unused local variable

* Remove another unused variable

* Correct typos and remove unused initialization

* Cleanup some code in OPCharCreate

* Remove unused function in client.cpp and undefined declaration.
Also the function potentially had a null pointer dereference according to Visual Studio.

zone/client.cpp

@@ -5531,7 +5531,6 @@ bool Client::TryReward(uint32 claim_id)
 	if (free_slot == 0xFFFFFFFF)
 		return false;
 
-	char errbuf[MYSQL_ERRMSG_SIZE];
 	std::string query = StringFormat("SELECT amount FROM account_rewards "
 					 "WHERE account_id = %i AND reward_id = %i",
 					 AccountID(), claim_id);
@@ -7997,7 +7996,6 @@ void Client::SetFactionLevel(uint32 char_id, uint32 npc_id, uint8 char_class, ui
 
 	for (int i = 0; i < MAX_NPC_FACTIONS; i++) {
 		int32 faction_before_hit;
-		int32 faction_to_use_for_messaging;
 		FactionMods fm;
 		int32 this_faction_max;
 		int32 this_faction_min;