Unrecognised ex-commands changes indentation

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Environment:

• VSCode Version: 1.14.2
• VsCodeVim Version: 0.9.0
• OS: Ubuntu Gnome 17.04

I have vim.enableNeovim enabled.

What happened:
When I write a command that (I imagine) isn't supported, the 4 space indentation in my Python code is turned into tabs and the bottom right of VS Code where it shows the indentation you're using is switched from "Spaces: 4" to "Tabs: 4". Even something that I thought should work, didn't: :%s/verticies/vertices/g
After a little experimenting, apparently anything the command bar doesn't recognise causes this behaviour, for example :asd

What did you expect to happen:
When writing :%s/verticies/vertices/g, I expected it to replace all instances of 'verticies' with 'vertices'.
When writing :asd, I expected a message saying it's not a recognised command.

How to reproduce it:
Open a Python source file that uses spaces for indentation, ensure your editor says "Spaces: 4" in bottom right, then open the command bar by pressing : and write anything that isn't an actual command and hit enter and observe that what was "Spaces: 4" has turned into "Tabs: 4" and indentation is now in tabs.

Reproduce this in a Python file using spaces, then trace the command-bar handling for an unrecognised ex-command such as :asd or the substitution example. Confirm where the editor indentation mode changes; done means unsupported commands report an error without converting spaces to tabs, while supported substitutions retain their expected behavior.