rpm: Fix patch to ensure variables aren't used uninitialised

rpm: Fix patch to ensure variables aren't used uninitialised

Recent patches were applied which removed a function which set the xx
variable. This means xx can be uninitalised and prerm functions can fail.

This adjusts the patch to ensure the xx value isn't used in such a way.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>