add parameter -p for mkdir to prevent error message if dir already exist

Hi,
Sometimes I will create the directory manually because I want to add something addition but just local modify, like local patch or pre-downloaded client & core, use parameter -p like others can prevent the error message, I think it's useful, and I checked all the mkdir command in this project, most of then already use this parameter, so I made the remaining mkdir had this parameter, hope this commit can be merged into the master branch, thanks.