Adjust single pack statement, fix up some quotes

* Moved over to using single quotes for strings that don't need
escaping or interpolation.
* Changed one pack spec to be "more correct". Thankfully, we were only
packing 0 so the endianness isn't a problem, however it should be
correct, hence the fix.

Author: OJ

lib/rex/payloads/meterpreter/config.rb

@@ -39,7 +39,7 @@ def to_str(item, size)
   end
 
   def to_wchar_t(item, size)
-    to_ascii(item, size).unpack("C*").pack("v*")
+    to_ascii(item, size).unpack('C*').pack('v*')
   end
 
   def to_ascii(item, size)
@@ -57,7 +57,7 @@ def session_block(opts)
       uuid                # the UUID
     ]
 
-    session_data.pack("VVVA*")
+    session_data.pack('VVVA*')
   end
 
   def transport_block(opts)
@@ -117,7 +117,7 @@ def extension_block(ext_name, file_extension)
     ext, o = load_rdi_dll(MetasploitPayloads.meterpreter_path("ext_server_#{ext_name}",
                                                               file_extension))
 
-    extension_data = [ ext.length, ext ].pack("VA*")
+    extension_data = [ ext.length, ext ].pack('VA*')
   end
 
   def config_block
@@ -143,9 +143,9 @@ def config_block
 
     # terminate the extensions with a 0 size
     if is_x86?
-      config << [0].pack("V")
+      config << [0].pack('V')
     else
-      config << [0].pack("Q")
+      config << [0].pack('Q<')
     end
 
     # and we're done