Upgrade blank passwords to bcrypt hashes

Previously, blank passwords were not upgraded to bcrypt hashes. This is
annoying and problematic because it makes it difficult to remove the old
password hashing system because those passwords might still be checked
against non-bcrypt hashes.

TShockAPI/DB/UserManager.cs

@@ -444,15 +444,11 @@ namespace TShockAPI.DB
 					UpgradePasswordWorkFactor(password);
 					return true;
 				}
-			} 
+			}
 			catch (SaltParseException)
 			{
 				if (String.Equals(HashPassword(password), Password, StringComparison.InvariantCultureIgnoreCase))
 				{
-					// Return true to keep blank passwords working but don't convert them to bcrypt.
-					if (Password == "non-existant password") {
-						return true;
-					}
 					// The password is not stored using BCrypt; upgrade it to BCrypt immediately
 					UpgradePasswordToBCrypt(password);
 					return true;