Restore correct shebang syntax

In commit 2056f51 I accidentally removed the "!" from the "#!"
construct on line 1.  This was not intentional, and has gone unnoticed
for some time because the script still works normally.

However, the shebang line also has a "-e" option deliberately placed
there to cause the script to exit with an error if any step of the
process fails -- this is precisely to prevent the script from printing
"Bootstrap complete!" when it has in fact not done its job, which has
confused many users in the past.

Breaking the "#!" meant that that -e was no longer having any effect.

Bootstrap.sh is not really the recommended approach to autotools
anymore, since autotools provides autoreconf to do exactly the same
thing in one step.  But years of habit are hard to break, and having a
script that declares victory when it has in fact completely failed is
not good.  This restores the intended behavior of the entire script
exiting with an error if any step in it fails.

bootstrap.sh

@@ -1,4 +1,4 @@
-#/bin/sh -e
+#!/bin/sh -e
 #
 #
 # Copyright (C) 2000-2026 The Xastir Group