website-update: Remove lockdir code.

Now that we're running as a systemd service, that will make sure
only one update runs at a time.

cron/scripts/website-update.sh

@@ -3,7 +3,6 @@
 set -e
 set -u
 
-LOCKDIR="/tmp/website-update.$(id -u)"
 SITEDIR=~/website
 PRODUCTION_BRANCH=master
 
@@ -11,12 +10,6 @@ git_rev_name() {
     git rev-parse --abbrev-ref --symbolic-full-name "$@"
 }
 
-if ! mkdir "$LOCKDIR"; then
-    test -d "$LOCKDIR"
-    exit $?
-fi
-trap 'rmdir "$LOCKDIR"' 0 INT TERM QUIT
-
 # If the checkout is not on the production branch,
 # assume maintenance is happening and stop.
 cd "$SITEDIR"