Saving config to startup should always be from running configuration.

[Sda79]

Hi,
This line of code in the netconf_config module : here always save the target configuration to the startup config, so by default the candidate to the startup.

However, saving configuration should probably be always from running to startup.

From experience it can be problematic with some Netconf servers like Nokia SROS : see paragraph 4.3.4.4 here. They don't allow copy_config from/to candidate. Which make sense because it is the purpose of a commit.

What do you think ? Shouldn't we change this behavior or add a new parameter to specify the source file ?
I could propose a merge request :)

Thanks