If we are going to warn about an "invalid" URL, at least tell what it is

As such the code handles it perfectly fine, and returns an error from
the function, but.

Change-Id: I356b8140381d3ccd21ff0a7f5c666552571b12f4

sal/osl/unx/file_misc.cxx

@@ -347,8 +347,9 @@ oslFileError SAL_CALL osl_getNextDirectoryItem(oslDirectory pDirectory,
 
 oslFileError SAL_CALL osl_getDirectoryItem(rtl_uString* ustrFileURL, oslDirectoryItem* pItem)
 {
-    SAL_WARN_IF((!ustrFileURL) || (ustrFileURL->length == 0), "sal.file", "Invalid file URL");
-    SAL_WARN_IF(!pItem, "sal.file", "pItem is nullptr");
+    SAL_WARN_IF((!ustrFileURL) || (ustrFileURL->length == 0), "sal.file",
+                "Invalid file URL " << (ustrFileURL ? ("'" + OUString(ustrFileURL) + "'") : OUString("(null)")));
+    SAL_WARN_IF(!pItem, "sal.file", "pItem is null");
 
     rtl_uString* ustrSystemPath = nullptr;
     oslFileError osl_error = osl_File_E_INVAL;