when the real {u,g}ids and the groups are original.
Move RevertToSelf and ImpersonateLoggedOnUser to the main line.
* uinfo.cc (uinfo_init): Reorganize. If CreateProcess was called
while impersonated, preserve the uids and gids and call
ImpersonateLoggedOnUser. Preserve the uids and gids on Win9X.
* exceptions.cc (error_start_init): Quote the pgm in the command.