Switch brp-compress to bash

commit f3f763e54d introduced the use of 'read -d' which is
bash specific.

Signed-off-by: Dirk Müller <dirk@dmllr.de>

scripts/brp-compress

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 # If using normal root, avoid changing anything.
 if [ -z "$RPM_BUILD_ROOT" ] || [ "$RPM_BUILD_ROOT" = "/" ]; then