Find conda when on a cloned conda-analytics env.

Created by: xabriel

On the new conda-analytics conda environment, we do not have the conda package available.

This is because when doing conda create --clone ... conda explicitly removes conda related packages. I presume the rationale is that only the base should typically include the conda package. This was never an issue on anaconda-wmf since that environment was using the --stacked flag.

In this PR we thus modify the sys.path to find conda on the base environment, if we detect that we are running on top of conda-analytics.