[studio] Update STAGE1_TOOLS_URL to Habitat account s3 bucket.
[studio] Update STAGE1_TOOLS_URL to Habitat account s3 bucket.

Signed-off-by: Fletcher Nichol <fnichol@nichol.ca>

Pull request: #756
Approved by: jtimberman

rsertelon/habitat,habitat-sh/habitat,nathenharvey/habitat,habitat-sh/habitat,georgemarshall/habitat,nathenharvey/habitat,habitat-sh/habitat,rsertelon/habitat,habitat-sh/habitat,georgemarshall/habitat,georgemarshall/habitat,georgemarshall/habitat,rsertelon/habitat,nathenharvey/habitat,rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,nathenharvey/habitat,georgemarshall/habitat,nathenharvey/habitat,nathenharvey/habitat,georgemarshall/habitat,habitat-sh/habitat,rsertelon/habitat,georgemarshall/habitat,habitat-sh/habitat,georgemarshall/habitat,habitat-sh/habitat