[PATCH] hooks--commit-msg: no silent exit on duplicate Signed-off-by lines

The commit-msg hook would silently exit if duplicate
Signed-off-by lines were found.  Users of git-commit would
not know it, unless they checked '$?'.  This patch makes the
commit-msg hook actually print out a message that duplicate
Signed-off-lines were found (and thus nothing were
committed).

Signed-off-by: Luben Tuikov <redacted>
---
 templates/hooks--commit-msg |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)