r22071: Make the error message for incorrect use of '-c' show the parameter as used.

r22071: Make the error message for incorrect use of '-c' show the parameter as used.

This means that smbpasswd -c user (which in htpasswd creates a new file)
and smbpasswd -c /not/my/smb.conf should give errors an admin will
think to chase down.

Andrew Bartlett
(This used to be commit 721375e14cfcef88061c9e4d4a1f3ca2f33fa9aa)