adds a .nil? check as well

Author: kernelsmith

lib/msf/core/db.rb

@@ -4869,7 +4869,7 @@ def import_nmap_noko_stream(args, &block)
 	# If you have Nokogiri installed, you'll be shunted over to
 	# that. Otherwise, you'll hit the old NmapXMLStreamParser.
 	def import_nmap_xml(args={}, &block)
-		return nil if args[:data].empty?
+		return nil if args[:data].nil? or args[:data].empty?
 		wspace = args[:wspace] || workspace
 		bl = validate_ips(args[:blacklist]) ? args[:blacklist].split : []