mapi: do not mandate bash for es*api/ABI-check

Seemingly there is nothing bash specific in these. The Debian
checkbashisms does not spot neither run in zsh.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>

src/mapi/es1api/ABI-check

@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/sh
 
 # Print defined gl.* functions not in GL ES 1.1 or in
 # (FIXME, none of these should be part of the ABI)

src/mapi/es2api/ABI-check

@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/sh
 
 # Print defined gl.* functions not in GL ES 3.0 or in
 # (FIXME, none of these should be part of the ABI)