Update compat-usrmerge to version 84.87 / rev 5 via SR 923737
    
    https://build.opensuse.org/request/show/923737
    by user lnussel + dimstar_suse
    - Fix logic for detecting conflicts with directories (boo#1191111)
    - exit file triggers early if alread usrmerged (forwarded request 923734 from lnussel)