[Lilypond-auto] Patchy report from grenouille

[grenouille]

16:55:18 (UTC) Begin LilyPond compile, previous commit at       
ac0e95c8112250bcaddf0bce57ba2980767a2f43
16:55:18 *** FAILED STEP ***
        merge from staging
        Command '['git', 'branch', 'test-master-lock', 'origin/master']' 
returned non-zero exit status 128
fatal: A branch named 'test-master-lock' already exists.