The flag-set that was returned is a pointer to the command's Flags(), which
is in itself passed by reference (as it is modified / set up).
This patch removes the flags return, to prevent assuming it's different than
the command's flags.
While SetupRootCommand is exported, a search showed that it's only used internally,
so changing the signature should not be a problem.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>