Make DoublePulsar check optional for MS17-010 scanner

[ghost]

Added an option that lets you choose whether or not to scan for DoublePulsar on MS17-010 vulnerable targets.

Verification

List the steps needed to make sure this thing works

• Start msfconsole
• use auxiliary/scanner/smb/smb_ms17_010
• Scan MS17-010 vulnerable target, with DoublePulsar infection
• Ensure both vulnerable and infected messages shown
• set CHECK_DOPU false
• Scan MS17-010 vulnerable target, with DoublePulsar infection
• Ensure only vulnerable message shown

[alrosenthal-r7]

Release Notes

An option that lets you choose whether or not to scan for DoublePulsar on MS17-010 vulnerable targets has been added to the auxiliary/scanner/smb/smb_ms17_010 module.