Set PYTHONUNBUFFERED for systemd managed python

This lets python scripts print to the journal.

Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/common/recipes-phosphor/obmc-phosphor-example-pydbus/files/obmc-phosphor-example-pydbus.service b/common/recipes-phosphor/obmc-phosphor-example-pydbus/files/obmc-phosphor-example-pydbus.service
index fbc50d3..27d9bfe 100644
--- a/common/recipes-phosphor/obmc-phosphor-example-pydbus/files/obmc-phosphor-example-pydbus.service
+++ b/common/recipes-phosphor/obmc-phosphor-example-pydbus/files/obmc-phosphor-example-pydbus.service
@@ -4,6 +4,7 @@
 [Service]
 Restart=always
 ExecStart=/usr/sbin/obmc-phosphor-example-pydbus
+Environment="PYTHONUNBUFFERED=1"
 
 [Install]
 WantedBy=multi-user.target