MAINTENANCE: Automated closing of pull requests.

This commit exists to close the following pull requests on Github:

Closes apache#3297 (close requested by 'andrewor14')
Closes apache#3345 (close requested by 'pwendell')
Closes apache#2729 (close requested by 'srowen')
Closes apache#2320 (close requested by 'pwendell')
Closes apache#4529 (close requested by 'andrewor14')
Closes apache#2098 (close requested by 'srowen')
Closes apache#4120 (close requested by 'andrewor14')