Restore MERGE_HEAD and CHERRY_PICK_HEAD without newline
Restore MERGE_HEAD and CHERRY_PICK_HEAD without newline

Including the trailing newline results in an error on Windows:
  fatal: Corrupt MERGE_HEAD file
  (<commit-hash>)

blech75/overcommit,oxocode/overcommit,TheSooth/overcommit,oxocode/overcommit,gnagel/overcommit,gnagel/overcommit,TheSooth/overcommit,blech75/overcommit