wrong bash.exe when installing Windows Subsystem for Linux

If you're following the instructions at https://msdn.microsoft.com/en-au/commandline/wsl/install_guide to get Microsoft's Linux environment installed, but you also have a Ruby devkit on your path, the "Run bash" instruction doesn't work.  Because it runs the devkit bash instead of the WSL bash.

You want "Run c:\windows\system32\bash" instead.