ws: Remove duplicate #defines in cockpitsshtransport.c

Closes #1301
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
ws: Fix screwed up debug message about destroying session

Closes #1302
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
ws: Move G_LOG_DOMAIN define to fix build on clang