Remove unnecessary variable assignment in SQLEncrypted.

Author: davexunit

lib/casserver/authenticators/sql_encrypted.rb

@@ -48,8 +48,6 @@ def validate(credentials)
     read_standard_credentials(credentials)
     raise_if_not_configured
 
-    user_model = self.user_model
-
     username_column = @options[:username_column] || "username"
     encrypt_function = @options[:encrypt_function] || 'user.encrypted_password == Digest::SHA256.hexdigest("#{user.encryption_salt}::#{@password}")'