Update brltty to rev 49 via SR 798836
    
    https://build.opensuse.org/request/show/798836
    by user olh + dimstar_suse
    - Update to version 6.1:
      + See ChangeLog for changes.
    - Rebased brltty-5.5-systemd-install.patch
    - api_version is now 0.8.0, and sover is now 0_8
    - Add brltty-gcc10.patch: fix build with -fno-common.
    - Adjust line to remove xsession file.
    - Remove brltty-alsa.patch