python: netcmd: remove OptionError alias to OptionValueError
The other methods in this file already raise optparse.OptionValueError
directly, except for two older ones.
They are using an alias which changes the name to OptionError, the
confusing part about this is that optparse.OptionError actually does
exist, so the incorrect alias needs to be removed.
Signed-off-by: Rob van der Linde <rob@catalyst.net.nz>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>