Add cwd to subprocess calls

[agjohnson]

We were assuming this path before, which defaulted to the path you
executed django from on the host machine. The cwd was used in commands
run on inside Docker however. On Linux dev environments, this path is
most likely missing.

By specifying paths, we will get paths that have been created inside the
container.

[humitos]

I don't follow what this fixes. What's the error that you were getting without applying these changes?

I've never experienced this before in my local environment.

[agjohnson]

My instance is broken between all my patches, but the error something like this in the virtualenv step:

can't cd to /home/anthony/secure/dev/readthedocs-corporate

It's because the application uses the cwd of the application, which does not exist in the docker container. Instead of just using the default cwd for these commands, we specify one so that the host system cwd isn't used.

Not sure why you wouldn't have hit this, unless you added extra paths into docker or change a setting i didn't change.

[humitos]

Not sure why you wouldn't have hit this, unless you added extra paths into docker or change a setting i didn't change.

I didn't change any setting related to this.

Maybe this is still a permission issue and since I'm creating my Docker image in a different way (#4608 (comment)) than you, I'm not experimenting this.

What about you, @stsewd?

[stsewd]

I haven't experiment this as well, I think that error is the same with the error permissions.

[humitos]

Well, I don't know what's happening but after pulling latest master in both (.org and .com) I started having this issue and this PR solves this.

I tried by building in .com and after applying this patch it worked.

So, I don't understand why it wasn't happening before and it's happening now.

[agjohnson]

Oh interesting. Perhaps we changed something with paths here lately.