bug#27858: Conda (on guix) does not activate environments

[Frederick Muriithi <fredmanglis@gmail.com>]

I have come across a bug on conda, installed via guix, that does not
seem to be present when conda is installed via the process at
https://conda.io/docs/install/quick.html#linux-miniconda-install

The issue
---------
Conda (on guix) does not activate environments

Command ran
-----------
source activate test-env

Expected result
---------------
The envinment should be activated, and the prompt changes from
`frederick@localhost:/tmp$` to `(test-guix-conda)
frederick@localhost:/tmp$`

Actual result
-------------
The terminal window is exited.

Additional information
----------------------
This behaviour is not present on conda installed via the process
presented in the conda documentation.

The environment(s) created by conda on guix are available on, and can
be activated by conda installed via the process in the conda
documentation.

I ran `bash -c "source activate test-env"` and the following error
message was displayed:

/gnu/store/f2dr9xbimg93pljm7xgmqb4cm5bxy98r-conda-4.3.16/bin/.deactivate-real:
line 59: return: can only `return' from a function or sourced script
/gnu/store/f2dr9xbimg93pljm7xgmqb4cm5bxy98r-conda-4.3.16/bin/.deactivate-real:
line 94: return: can only `return' from a function or sourced script

I would appreciate any help that would help in resolving this issue.