git-sh-setup: die if outside git repository.

Now all the users of this script detect its exit status and die,
complaining that it is outside git repository.  So move the code
that dies from all callers to git-sh-setup script.

Signed-off-by: Junio C Hamano <junkio@cox.net>

git-octopus.sh

@@ -4,7 +4,7 @@
 #
 # Resolve two or more trees recorded in $GIT_DIR/FETCH_HEAD.
 #
-. git-sh-setup || die "Not a git archive"
+. git-sh-setup
 
 usage () {
     die "usage: git octopus"