Fix segfault on Tails

src/qt/MoneroSettings.cpp

@@ -147,6 +147,7 @@ void MoneroSettings::reset()
 {
     if (this->m_initialized && this->m_settings && !this->m_changedProperties.isEmpty())
         this->store();
+    if (this->m_settings)
         delete this->m_settings;
 }
 

src/qt/MoneroSettings.h

@@ -72,7 +72,7 @@ private:
     void store();
 
     QHash<const char *, QVariant> m_changedProperties;
-    QSettings *m_settings;
+    QSettings *m_settings = NULL;
     QString m_fileName = QString("");
     bool m_initialized = false;
     int m_timerId = 0;