Add absolute import for pyinstaller compatibility
Add absolute import for pyinstaller compatibility

Adding an absolute import here solves an error when compiling apps with pyinstaller that use statsmodels.
pyinstaller: https://github.com/pyinstaller/pyinstaller
issue: https://github.com/pyinstaller/pyinstaller/issues/2183
ChadFulton/statsmodels,jseabold/statsmodels,bashtage/statsmodels,josef-pkt/statsmodels,josef-pkt/statsmodels,jseabold/statsmodels,josef-pkt/statsmodels,statsmodels/statsmodels,bashtage/statsmodels,statsmodels/statsmodels,ChadFulton/statsmodels,josef-pkt/statsmodels,ChadFulton/statsmodels,jseabold/statsmodels,bashtage/statsmodels,josef-pkt/statsmodels,statsmodels/statsmodels,bashtage/statsmodels,ChadFulton/statsmodels,ChadFulton/statsmodels,jseabold/statsmodels,josef-pkt/statsmodels,ChadFulton/statsmodels,statsmodels/statsmodels,statsmodels/statsmodels,bashtage/statsmodels,bashtage/statsmodels,jseabold/statsmodels,statsmodels/statsmodels