Do not require clean tree when reverting and cherry-picking.

My stupidity deserved to be yelled at by Linus ... there is no reason
to require the working tree to be clean when merging -- the only
requirements are index to match HEAD commit and the paths involved in
merge are up to date in the working tree.  Revert and cherry-pick are
just specialized forms of merge, and the requirements should be the
same.

Remove the 'general purpose routine to make sure tree is clean' from
git-sh-setup, to prevent me from getting tempted again.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

git-revert.sh

@@ -56,9 +56,12 @@ t)
 		die "Your index file is unmerged."
 	;;
 *)
-	check_clean_tree || die "Cannot run $me from a dirty tree."
 	head=$(git-rev-parse --verify HEAD) ||
 		die "You do not have a valid HEAD"
+	files=$(git-diff-index --cached --name-only $head) || exit
+	if [ "$files" ]; then
+		die "Dirty index: cannot $me (dirty: $files)"
+	fi
 	;;
 esac
 

git-sh-setup.sh

@@ -17,17 +17,6 @@ die() {
 	exit 1
 }
 
-check_clean_tree() {
-    dirty1_=`git-update-index -q --refresh` && {
-    dirty2_=`git-diff-index --name-only --cached HEAD`
-    case "$dirty2_" in '') : ;; *) (exit 1) ;; esac
-    } || {
-	echo >&2 "$dirty1_"
-	echo "$dirty2_" | sed >&2 -e 's/^/modified: /'
-	(exit 1)
-    }
-}
-
 [ -h "$GIT_DIR/HEAD" ] &&
 [ -d "$GIT_DIR/refs" ] &&
 [ -d "$GIT_OBJECT_DIRECTORY/00" ]