cm: bootanimation: Fail the build if mogrify is absent

#

# Copyright (C) 2016 The CyanogenMod Project

#               2017 The LineageOS Project

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

ifeq ($(TARGET_BOOTANIMATION),)

    TARGET_BOOTANIMATION := $(TARGET_GENERATED_BOOTANIMATION)

    ifeq ($(shell command -v convert),)

    ifeq ($(shell command -v mogrify),)

        $(info **********************************************)

        $(info The boot animation could not be generated as)

        $(info ImageMagick is not installed in your system.)