smb : fix misuse of smb-force-v1 bool flag

This change fix how the smb-force-v1 option was set when we try to connect to a SMB server.

Given smb-force-v1 is a vlc bool var type, the only way to disable it is by :

• not adding the option at all
• set the option key to nosmb-force-v1 or no-smb-force-v1

Given how b_isno function var is set and mutated in variables.c:var_OptionParse, if smb-force-v1 option key is added, even with a NO value resulting in smb-force-v1=0, the bool var value will be always true.

This change was required to be able to use libsmb2 when libdsm fails probing given the host name isn't a netbios name, like when we set a smb server on macOS and the host name is <machine-name>.local