Fix bashisms in kernel-install scripts

Remove negotiation from `-z` to test for non-emptiness instead of
previously added version reversing those tests logic.

Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>

debian/patches/apertis/Remove-bashisms-from-the-UEFI-entries-generator.patch

@@ -2,7 +2,7 @@ From: Denis Pynkin <denis.pynkin@collabora.com>
 Date: Thu, 14 Feb 2019 00:04:13 +0300
 Subject: Remove bashisms from the UEFI entries generator
 
-- Use [ not [[ and -n to test for non-emptiness
+- Use [ not [[ and -z to test for non-emptiness
 - Use shell lists instead of arrays
 
 Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>
@@ -29,7 +29,7 @@ index d096745..9e1b910 100644
 +INITRD_OPTIONS_START="4"
  
 -if ! [[ $KERNEL_INSTALL_MACHINE_ID ]]; then
-+if ! [ -n $KERNEL_INSTALL_MACHINE_ID ]; then
++if [ -z "$KERNEL_INSTALL_MACHINE_ID" ]; then
      exit 0
  fi
  
@@ -55,7 +55,7 @@ index d096745..9e1b910 100644
  fi
  
 -if ! [[ $KERNEL_IMAGE ]]; then
-+if ! [ -z "$KERNEL_IMAGE" ]; then
++if [ -z "$KERNEL_IMAGE" ]; then
      exit 1
  fi
  
@@ -68,7 +68,7 @@ index d096745..9e1b910 100644
  fi
  
 -if ! [[ $PRETTY_NAME ]]; then
-+if ! [ -z "$PRETTY_NAME" ]; then
++if [ -z "$PRETTY_NAME" ]; then
      PRETTY_NAME="Linux $KERNEL_VERSION"
  fi
  

debian/patches/apertis/Remove-bashisms-from-the-depmod-wrapper.patch

@@ -18,7 +18,7 @@ index 3850eac..2b026da 100644
 +++ b/src/kernel-install/50-depmod.install
 @@ -1,4 +1,4 @@
 -#!/usr/bin/env bash
-+#!//bin/sh
++#!/bin/sh
  # -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
  # ex: ts=8 sw=4 sts=4 et filetype=sh
  

debian/patches/apertis/Remove-bashisms-from-the-entry-directory-plugin.patch

@@ -3,7 +3,7 @@ From: Denis Pynkin <denis.pynkin@collabora.com>
 Date: Mon, 26 Apr 2021 23:00:48 +0300
 Subject: Remove bashisms from the entry directory plugin
 
-- Use [ not [[ and -n to test for non-emptiness
+- Use [ not [[ and -z to test for non-emptiness
 
 Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>
 ---
@@ -25,7 +25,7 @@ index 21c09fa..e2fc396 100644
  INITRD_OPTIONS_START="5"
  
 -if ! [[ $KERNEL_INSTALL_MACHINE_ID ]]; then
-+if ! [ -z "$KERNEL_INSTALL_MACHINE_ID" ]; then
++if [ -z "$KERNEL_INSTALL_MACHINE_ID" ]; then
      exit 0
  fi