lib: Drop needless ret variables

lib: Drop needless ret variables

There are few places where a return variable is introduced (ret
or retval), but then is never changed and is then passed to
return. Well, we can return the value that the variable is
initialized to directly.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>