Optimize skip logic in #update_all_module_details

MSP-11368

Use `Hash<String, Set<String>>` instead of `Array<(String, String)>` so
that `include?` call is faster because (1) it's only search through
reference names of the same module_type and (2) `Set#include?` is faster
than `Array#include?`.  This change is a 8.20% average reduction in boot
time compare to b863978, for a overall
reduction of 40.95% over b5c3c87.
See statistics at
https://docs.google.com/spreadsheets/d/1TnZIUFIR1S5nCnkeM-7XR3AVSbyCl39x2mItJKJCOqg/edit?usp=sharing
and data at
https://drive.google.com/folderview?id=0Bx1hRHfpRW92VEFvQ2FaN3RoWWs&usp=drive_web

Author: limhoff-r7

lib/msf/core/db_manager.rb

@@ -366,7 +366,9 @@ def update_all_module_details
     ActiveRecord::Base.connection_pool.with_connection do
 
       refresh = []
-      skipped = []
+      skip_reference_name_set_by_module_type = Hash.new { |hash, module_type|
+        hash[module_type] = Set.new
+      }
 
       Mdm::Module::Detail.find_each do |md|
 
@@ -385,7 +387,8 @@ def update_all_module_details
           next
         end
 
-        skipped << [md.mtype, md.refname]
+        skip_reference_name_set = skip_reference_name_set_by_module_type[md.mtype]
+        skip_reference_name_set.add(md.refname)
       end
 
       refresh.each { |md| md.destroy }
@@ -398,8 +401,10 @@ def update_all_module_details
           ['encoder', framework.encoders],
           ['nop', framework.nops]
       ].each do |mt|
+        skip_reference_name_set = skip_reference_name_set_by_module_type[mt[0]]
+
         mt[1].keys.sort.each do |mn|
-          next if skip?(skipped, [mt[0], mn])
+          next if skip_reference_name_set.include? mn
           obj = mt[1].create(mn)
           next if not obj
           begin
@@ -419,10 +424,6 @@ def update_all_module_details
     self.framework.cache_thread = nil
   end
 
-  def skip?(skipped, entry)
-    skipped.include?(entry)
-  end
-
   # Creates an Mdm::Module::Detail from a module instance.
   #
   # @param module_instance [Msf::Module] a metasploit module instance.