Fix direct datastore assignments to pass msftidy

This patch should allow ```rport``` and ```smbdirect``` to be modified at runtime without touching the actual datastore options.

 - [ ] Test the module against a Windows SMB service
datastore['RPORT'] is unregistered just a few lines above this, so users can't even set it anyways.  I'm guessing you should just remove this.  Similarly for SMBDIRECT, which isn't even used.  The module is hardcoded to use 139 and 445 without and with smbdirect, respectively.