OpenGL error for Qt package on Azure

The following pull request is showing errors on Azure Linux:

https://github.com/conda-forge/glue-core-feedstock/pull/24

The error in question is:

```
2019-02-04T11:20:49.1560302Z Traceback (most recent call last):
2019-02-04T11:20:49.1560774Z File "/home/conda/feedstock_root/build_artifacts/glue-core_1549278994524/test_tmp/run_test.py", line 8, in
2019-02-04T11:20:49.1560860Z import glue.app.qt
2019-02-04T11:20:49.1561468Z File "/home/conda/feedstock_root/build_artifacts/glue-core_1549278994524/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehol/lib/python3.7/site-packages/glue/app/qt/__init__.py", line 3, in
2019-02-04T11:20:49.1561563Z from .application import GlueApplication # noqa
2019-02-04T11:20:49.1561945Z File "/home/conda/feedstock_root/build_artifacts/glue-core_1549278994524/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehol/lib/python3.7/site-packages/glue/app/qt/application.py", line 11, in
2019-02-04T11:20:49.1562023Z from qtpy import QtCore, QtWidgets, QtGui, compat
2019-02-04T11:20:49.1562394Z File "/home/conda/feedstock_root/build_artifacts/glue-core_1549278994524/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehol/lib/python3.7/site-packages/qtpy/QtWidgets.py", line 22, in
2019-02-04T11:20:49.1562461Z from PyQt5.QtWidgets import *
```

and the full log can be found here:

https://dev.azure.com/conda-forge/feedstock-builds/_build/results?buildId=10615&view=logs&jobId=c5e1d14a-022b-53aa-94b2-4ac2d6a3ed6b

The recipe works fine on CircleCI.