Auto merge of #322 - larsbergstrom:windows2, r=aneeshusa
Auto merge of #322 - larsbergstrom:windows2, r=aneeshusa

use bash to run the mach stuff

r? @aneeshusa @edunham

Ugh, I forgot that we need to execute bash.exe in order to run the mach command successfully. See:
https://github.com/servo/servo/blob/master/appveyor.yml#L45

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servo/saltfs,ALikhachev/saltfs,setupminimal/saltfs,UK992/saltfs,setupminimal/saltfs,rwaweber/saltfs,UK992/saltfs,ALikhachev/saltfs,rwaweber/saltfs,setupminimal/saltfs,UK992/saltfs,ALikhachev/saltfs,rwaweber/saltfs,servo/saltfs