Fix test data build script

It uses bash specific features, so it should not claim /bin/sh in
shebang. We also want to use `set -e` to catch possible errors instead
of claiming success every time.

Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

tests/data/specs/build.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 # run this script to (re-)generate ../repo and ../repo-krb5-lookaside directories
 
@@ -7,7 +7,7 @@
 #  * rpmbuild
 
 
-#set -e
+set -e
 
 
 DIR=$(dirname $(readlink -f $0))