suggestion: move from wget to requests

globus_sdk already depends on requests:
```
(git)lena:~datalad/GLOBUSannex[testremote]git
$> pip install globus_sdk
Collecting globus_sdk
Using cached https://files.pythonhosted.org/packages/be/c1/ccf8e8ebeb229887e6355e87e9cc9f07e06b1661b3c6e50311566bae9f28/globus_sdk-1.8.0-py2.py3-none-any.whl
Requirement already satisfied: six<2.0.0,>=1.10.0 in /usr/lib/python3/dist-packages (from globus_sdk) (1.12.0)
Requirement already satisfied: pyjwt[crypto]<2.0.0,>=1.5.3 in /usr/lib/python3/dist-packages (from globus_sdk) (1.7.1)
Requirement already satisfied: requests<3.0.0,>=2.9.2 in /usr/lib/python3/dist-packages (from globus_sdk) (2.21.0)
Requirement already satisfied: cryptography>=1.4 in /usr/lib/python3/dist-packages (from pyjwt[crypto]<2.0.0,>=1.5.3->globus_sdk) (2.6.1)
Installing collected packages: globus-sdk
Successfully installed globus-sdk-1.8.0
```
so imho would be better just to use requests. `wget` module seems to be not maintained since 2015 so, even though it is quite minimalistic, I expect it to eventually break with newer python versions.

The issue names no files or tests. Begin by locating the wget dependency and its call sites in git-annex-remote-globus, then check the existing requests dependency; done means the remote uses requests instead of wget without changing its behavior.

Written by the indexing model from the issue text.