qt: Use correct conversion function for boost::path datadir

Fixes #9089.

src/qt/clientmodel.cpp

@@ -6,6 +6,7 @@
 
 #include "bantablemodel.h"
 #include "guiconstants.h"
+#include "guiutil.h"
 #include "peertablemodel.h"
 
 #include "alert.h"
@@ -198,7 +199,7 @@ QString ClientModel::formatClientStartupTime() const
 
 QString ClientModel::dataDir() const
 {
-    return QString::fromStdString(GetDataDir().string());
+    return GUIUtil::boostPathToQString(GetDataDir());
 }
 
 void ClientModel::updateBanlist()

src/qt/paymentserver.cpp

@@ -85,7 +85,7 @@ static QString ipcServerName()
     // Append a simple hash of the datadir
     // Note that GetDataDir(true) returns a different path
     // for -testnet versus main net
-    QString ddir(QString::fromStdString(GetDataDir(true).string()));
+    QString ddir(GUIUtil::boostPathToQString(GetDataDir(true)));
     name.append(QString::number(qHash(ddir)));
 
     return name;