Made --http-no-cache false by default

doc/manual-src/en/aria2c.rst

@@ -379,10 +379,10 @@ HTTP Specific Options
 
 .. option:: --http-no-cache[=true|false]
 
-   Send Cache-Control: no-cache and Pragma: no-cache header to avoid
+   Send ``Cache-Control: no-cache`` and ``Pragma: no-cache`` header to avoid
    cached content.  If ``false`` is given, these headers are not sent
    and you can add Cache-Control header with a directive you like
-   using :option:`--header` option. Default: ``true``
+   using :option:`--header` option. Default: ``false``
 
 .. option:: --http-user=<USER>
 

src/OptionHandlerFactory.cc

@@ -1188,7 +1188,7 @@ std::vector<OptionHandler*> OptionHandlerFactory::createOptionHandlers()
     OptionHandler* op(new BooleanOptionHandler
                       (PREF_HTTP_NO_CACHE,
                        TEXT_HTTP_NO_CACHE,
-                       A2_V_TRUE,
+                       A2_V_FALSE,
                        OptionHandler::OPT_ARG));
     op->addTag(TAG_HTTP);
     op->setInitialOption(true);