Don't ignore errors on encrypting password in SMBTcon

Although unlikely to fail (and tree connect does not commonly send
a password since SECMODE_USER is the default for most servers)
do not ignore errors on SMBNTEncrypt in SMB Tree Connect.

Reported by Coverity (CID 1226853)

Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Acked-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Jeff Layton <jlayton@poochiereds.net>