Merge branch 'pw/am-rebase-read-author-script'

Unify code to read the author-script used in "git am" and the commands that use the sequencer machinery, e.g. "git rebase -i". * pw/am-rebase-read-author-script: sequencer: use read_author_script() add read_author_script() to libgit am: rename read_author_script() am: improve author-script error reporting am: don't die in read_author_script()