session: set the XDG_SEAT and XDG_RUNTIME_DIR environments in all cases
session: set the XDG_SEAT and XDG_RUNTIME_DIR environments in all cases

Change-Id: Icf9b737743420866f784edc445ff6d1a0a156f37

again4you/tlm,avalluri/tlm,ipuustin/tlm,ipuustin/tlm,avalluri/tlm,01org/tlm,zhengcq315/tlm,again4you/tlm,01org/tlm,zhengcq315/tlm