define die() for scripts that use it.

As a fallout from not using git-sh-setup in scripts that can
operate from a subdirectory, we lost definition of die() from
them.  It might make sense to do some cleanup to consolidate
them back again, but this should suffice for now.

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

git-add.sh

@@ -1,5 +1,10 @@
 #!/bin/sh
 
+die () {
+    echo >&2 "$*"
+    exit 1
+}
+
 usage() {
     die "usage: git add [-n] [-v] <file>..."
 }

git-branch.sh

@@ -2,6 +2,11 @@
 
 GIT_DIR=`git-rev-parse --git-dir` || exit $?
 
+die () {
+    echo >&2 "$*"
+    exit 1
+}
+
 usage () {
     echo >&2 "usage: $(basename $0)"' [-d <branch>] | [[-f] <branch> [start-point]]
 

git-diff.sh

@@ -9,6 +9,11 @@ files=$(git-rev-parse --no-revs --no-flags --sq "$@")
 
 : ${flags:="'-M' '-p'"}
 
+die () {
+    echo >&2 "$*"
+    exit 1
+}
+
 # I often say 'git diff --cached -p' and get scolded by git-diff-files, but
 # obviously I mean 'git diff --cached -p HEAD' in that case.
 case "$rev" in

git-merge-octopus.sh

@@ -8,6 +8,11 @@
 LF='
 '
 
+die () {
+    echo >&2 "$*"
+    exit 1
+}
+
 # The first parameters up to -- are merge bases; the rest are heads.
 bases= head= remotes= sep_seen=
 for arg

git-tag.sh

@@ -8,6 +8,11 @@ usage () {
     exit 1
 }
 
+die () {
+    echo >&2 "$*"
+    exit 1
+}
+
 annotate=
 signed=
 force=

git-verify-tag.sh

@@ -2,6 +2,11 @@
 
 GIT_DIR=`git-rev-parse --git-dir` || exit $?
 
+die () {
+    echo >&2 "$*"
+    exit 1
+}
+
 type="$(git-cat-file -t "$1" 2>/dev/null)" ||
 	die "$1: no such object."