update-mail-to-commit-notes.sh: fix incorrect variable name

In b6d1ca5 (scripts: make shell scripts generic with new vars,
2022-01-19), the error messages were made more generic by abstracting
the concrete URLs into variables. However, in one instance, the variable
name was misspelled.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

script/update-mail-to-commit-notes.sh

@@ -21,7 +21,7 @@ git_remote="${GITGIT_GIT_REMOTE:-https://github.com/gitgitgadget/git}"
 update_gitgit_dir () {
 	test -d "$GITGIT_DIR" ||
 	git clone $git_remote "$GITGIT_DIR" ||
-	die "Could not clone $gitremote to $GITGIT_DIR"
+	die "Could not clone $git_remote to $GITGIT_DIR"
 
 	git -C "$GITGIT_DIR" fetch $git_remote \
 		refs/notes/mail-to-commit:refs/notes/mail-to-commit ||