Debugger: Fix some breakpoint file name display breakage

For unclaimed breakpoints the wodking directory was shown
as path.

Amends commit a7dd0e50a2.

Change-Id: I9614b3672d32fb18e35dc98c12a60e3b27eebf84
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/debugger/breakpoint.cpp

@@ -378,6 +378,7 @@ void BreakpointParameters::updateFromGdbOutput(const GdbMi &bkpt)
     QString name;
     if (!fullName.isEmpty()) {
         name = cleanupFullName(fullName);
+        fileName = Utils::FilePath::fromString(name);
         //if (data->markerFileName().isEmpty())
         //    data->setMarkerFileName(name);
     } else {