Build fix for WINCE to qfsfileengine_win.cpp

QFileSystemEngine::currentPath() returns QFileSystemEntry, but
this method expects QString return value.
-> Code does not compile for WinCE

Switched code to use "QFileSystemEngine::currentPath().filePath()"
correspondigly as Windows desktop does if filename does not contain
drive letter. This is ok, since WinCE does not support drive letters.

Task-number: QTBUG-22499
Change-Id: Ic4935357c40cda30efcd2e1c7d69bf2ef7b31dd0
Reviewed-by: Joerg Bornemann <joerg.bornemann@nokia.com>
Reviewed-by: Andreas Holzammer <andreas.holzammer@kdab.com>

src/corelib/io/qfsfileengine_win.cpp

@@ -550,7 +550,7 @@ QString QFSFileEngine::currentPath(const QString &fileName)
     return ret;
 #else
     Q_UNUSED(fileName);
-    return QFileSystemEngine::currentPath();
+    return QFileSystemEngine::currentPath().filePath();
 #endif
 }