development.middleware: Use "USERNAME" instead of "LOGNAME" on Windows

Closes #6
8 jobs for master in 52 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #61558
py27-django110

00:00:22

89.0%
passed #61559
py27-django111

00:00:22

89.0%
passed #61557
py27-django18

00:00:21

89.0%
passed #61561
py36-django110

00:00:22

90.0%
passed #61571
py36-django111

00:00:14

90.0%
passed #61560
py36-django18

00:00:23

90.0%
passed #61563
py36-django20

00:00:14

90.0%
failed #61562
py36-django111

00:00:05