Revert "lib: Ensure we don't find bind mounts for device target"
    
    Resolves: https://issues.redhat.com/browse/RHEL-56832
    Upstream Status: RHEL-only
    
    This reverts commit 099aead590608cd9edb49acf73873b03b88576b6.
    
    Currently get_mntpoint_from_target incorrectly return empty result for
    targets that contain square bracket '[', e.g
     - eng.redhat.com:/srv/[nfs]
     - [2620:52:0:a1:217:38ff:fe01:131]:/srv/[nfs]
     - /dev/mapper/rhel[disk]
    
    get_mntpoint_from_target is also used in several places. To avoid
    RHEL-56832 and other possible regressions, revert the bad commit.
    
    Suggested-by: Dave Young <dyoung@redhat.com>
    Signed-off-by: Coiby Xu <coxu@redhat.com>