Add a :debug-clear-ssl-errors command.

doc/help/commands.asciidoc

@@ -1226,6 +1226,7 @@ These commands are mainly intended for debugging. They are hidden if qutebrowser
 |Command|Description
 |<<debug-all-objects,debug-all-objects>>|Print a list of  all objects to the debug log.
 |<<debug-cache-stats,debug-cache-stats>>|Print LRU cache stats.
+|<<debug-clear-ssl-errors,debug-clear-ssl-errors>>|Clear remembered SSL error answers.
 |<<debug-console,debug-console>>|Show the debugging console.
 |<<debug-crash,debug-crash>>|Crash for debugging purposes.
 |<<debug-dump-page,debug-dump-page>>|Dump the current page's content to a file.
@@ -1241,6 +1242,10 @@ Print a list of  all objects to the debug log.
 === debug-cache-stats
 Print LRU cache stats.
 
+[[debug-clear-ssl-errors]]
+=== debug-clear-ssl-errors
+Clear remembered SSL error answers.
+
 [[debug-console]]
 === debug-console
 Show the debugging console.

qutebrowser/browser/commands.py

@@ -1764,3 +1764,10 @@ class CommandDispatcher:
 
             QApplication.postEvent(receiver, press_event)
             QApplication.postEvent(receiver, release_event)
+
+    @cmdutils.register(instance='command-dispatcher', scope='window',
+                       debug=True)
+    def debug_clear_ssl_errors(self):
+        """Clear remembered SSL error answers."""
+        nam = self._current_widget().page().networkAccessManager()
+        nam.clear_all_ssl_errors()

qutebrowser/browser/network/networkmanager.py

@@ -235,6 +235,11 @@ class NetworkManager(QNetworkAccessManager):
             reply.ignoreSslErrors()
             self._accepted_ssl_errors[host_tpl] += errors
 
+    def clear_all_ssl_errors(self):
+        """Clear all remembered SSL errors."""
+        self._accepted_ssl_errors.clear()
+        self._rejected_ssl_errors.clear()
+
     @pyqtSlot(QUrl)
     def clear_rejected_ssl_errors(self, url):
         """Clear the rejected SSL errors on a reload.