Utils: Be a bit more informative in failing FilePath accesses

Change-Id: I2e30998d2d5cd3159b28996d1102c65cbb9ad03b
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/libs/utils/filepath.cpp

@@ -873,7 +873,7 @@ DeviceFileAccess *FilePath::fileAccess() const
 
     static DeviceFileAccess dummy;
     DeviceFileAccess *access = s_deviceHooks.fileAccess(*this);
-    QTC_ASSERT(access, return &dummy);
+    QTC_ASSERT(access, qDebug() << toString(); return &dummy);
     return access;
 }