[SHELL32] Do not format the partition if it's a system drive

[SHELL32] Do not format the partition if it's a system drive

Implement a sanity check helper which determines if the partition is a system drive or not based on the %SystemDrive% environment variable, preventing the user from nuking accidentally the partition with ReactOS system files installed. :P

NOTE: This code serves as a temporary measure to prevent accidental formatting of the system drive. In the future most of this code has to be totally rewritten (and stopping syncing with WINE altogether) as well as FMIFS library code so that we're on par in terms of compatibility with Windows.