fix the error of parsing the container environ variable for osbuild
    
    Resolves: bz2024976
    Upstream: Fedora
    Conflict: None
    
    commit 6a3ce83a60c7107112d576223175410b180a41a0
    Author: Coiby Xu <coxu@redhat.com>
    Date:   Wed Jan 19 11:16:29 2022 +0800
    
        fix the error of parsing the container environ variable for osbuild
    
        The environment variable entries in /proc/[pid]/environ are separated by
        null bytes instead of by spaces. Update the sed regex to fix this issue.
    
        Note that,
          1. this patch also fixes a issue which is kdumpctl would try to reset
             crashkernel even osbuild has provided custom crashkernel value.
          2. kernel hook 92-crashkernel.install installed by kexec-tools is
             guaranteed to be ran by kernel-install. kexec-tools doesn't recommend
             kernel so there is no guarantee kernel is installed after kexec-tools.
             But dnf invokes kernel-install in the posttrans scriptlet (of kernel-core)
             which is always ran after all packages including kexec-tools and kernel
             in a dnf transaction.
          3. To be able to do unit tests, the logic of reading environment variable
             has been extracted as a separate function.
    
        Fixes: ddd428a ("set up kernel crashkernel for osbuild in kernel hook")
        Signed-off-by: Coiby Xu <coxu@redhat.com>
        Reviewed-by: Pingfan Liu <piliu@redhat.com>
        Reviewed-by: Philipp Rudo <prudo@redhat.com>
    
    Signed-off-by: Coiby Xu <coxu@redhat.com>