[Cleanup] Remove unused SaveBackup in client.h (#3030)

# Notes
- This is unused and does nothing in both Perl and Lua.

zone/client.h

@@ -353,8 +353,7 @@ public:
 	void UpdateLFP();
 
 	virtual bool Save() { return Save(0); }
-					bool Save(uint8 iCommitNow); // 0 = delayed, 1=async now, 2=sync now
-					void SaveBackup();
+	bool Save(uint8 iCommitNow); // 0 = delayed, 1=async now, 2=sync now
 
 	/* New PP Save Functions */
 	bool SaveCurrency(){ return database.SaveCharacterCurrency(this->CharacterID(), &m_pp); }