cppcheck: redundantAssignment

Let's not forget the result of RegDeleteValueA call

Change-Id: I9458040bc3a8960ab740ee3c5211eaa9ba24b1aa
Reviewed-on: https://gerrit.libreoffice.org/7772Tested-by: David Tardon <dtardon@redhat.com>
Reviewed-by: David Tardon <dtardon@redhat.com>

shell/source/win32/shlxthandler/shlxthdl.cxx

@@ -289,7 +289,7 @@ namespace /* private */
                 hkey,
                 ClsidToString(Clsid).c_str());
 
-            rc = RegCloseKey(hkey);
+            rc |= RegCloseKey(hkey);
         }
 
         return rc == ERROR_SUCCESS ? S_OK : E_FAIL;