These Coverity warnings all relate to the user of g_setenv() where the
return result isn't checked.
An additional void function g_setenv_log() is provided which logs
failures to set environment variables, and returns no status. This is
used in all the places where g_setenv_is currently called.
Now that authentication/authorization and session creation are
happening in the same process, there is no need for a separate call
to finish an auth session. This change prevents the upper software
layers from needing to track whether auth_start_session() has been
called or not.