Fixes lack of support for MetasploitV5 tag

 rapid7#4184

* Appears to have been overlooked somehow in the pre-BlackHat crunch
* V5 will not support credentials
* We are implementing full-workspace zip import/export for credentials

Author: trevrosen

lib/msf/core/db_manager/import.rb

@@ -302,6 +302,9 @@ def import_filetype_detect(data)
         when /MetasploitV4/
           @import_filedata[:type] = "Metasploit XML"
           return :msf_xml
+        when /MetasploitV5/
+          @import_filedata[:type] = "Metasploit XML"
+          return :msf_xml
         when /netsparker/
           @import_filedata[:type] = "NetSparker XML"
           return :netsparker_xml