Attempt to recover from network failures

QNetworkAccessManager which is  used for all network  traffic does not
automatically  recover  from  network  outages. This  patch  tries  to
reestablish network accessibility before any requests are attempted.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6471 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

DisplayManual.cpp

@@ -49,6 +49,11 @@ public:
 
   void display (QUrl const& url, QString const& name_we)
   {
+    if (QNetworkAccessManager::Accessible != qnam_->networkAccessible ()) {
+      // try and recover network access for QNAM
+      qnam_->setNetworkAccessible (QNetworkAccessManager::Accessible);
+    }
+
     // try and find a localized manual
     auto lang = QLocale::system ().name ();
     // try for language and country first