Make sure that relpath gets a value

Even if we are not asking for normalized paths, we need to return a
value in the relpath.  This modifies 574bef2237

Fixes https://gitlab.com/kicad/code/kicad/issues/9363

common/widgets/grid_text_button_helpers.cpp

@@ -392,6 +392,10 @@ protected:
                     lastPath = NormalizePath( dlg.GetDirectory(), &Pgm().GetLocalEnvVariables(),
                                               m_normalizeBasePath );
                 }
+                else
+                {
+                    relPath = filePath;
+                }
 
                 SetValue( relPath );
 
@@ -417,6 +421,10 @@ protected:
                     relPath = NormalizePath( filePath, &Pgm().GetLocalEnvVariables(),
                                              m_normalizeBasePath );
                 }
+                else
+                {
+                    relPath = filePath;
+                }
 
                 SetValue( relPath );