Fix installing bundler gem for errands on Ruby 3.3 (#617)

Author: sethboyles

jobs/blobstore_benchmark/templates/bpm.yml.erb

@@ -3,4 +3,5 @@ processes:
     executable: /var/vcap/jobs/blobstore_benchmark/bin/run
     args:
     - run
+    ephemeral_disk: true
 

jobs/rotate_cc_database_key/templates/bpm.yml.erb

@@ -4,3 +4,4 @@ processes:
   executable: /var/vcap/jobs/rotate_cc_database_key/bin/run
   args:
   - run
+  ephemeral_disk: true

shared_job_templates/ruby_version.sh.erb

@@ -5,12 +5,18 @@ CC_PACKAGE_DIR="${BOSH_PACKAGES_DIR:-/var/vcap/packages}/cloud_controller_ng"
 BUNDLER_VERSION=$(grep "BUNDLED WITH" ${CC_PACKAGE_DIR}/cloud_controller_ng/Gemfile.lock -A 1 | grep -v "BUNDLED" | awk '{print $1}')
 
 # Install the vendored bundler if it's not already installed
-# Use a lock file to avoid concurrent installations
-BUNDLER_LOCK_FILE="/var/vcap/sys/run/bundler_install.lock"
-mkdir -p "$(dirname $BUNDLER_LOCK_FILE)"
-(
-  flock -x 200
-  if ! gem list -i bundler -v $BUNDLER_VERSION > /dev/null 2>&1; then
+if ! gem list -i bundler -v $BUNDLER_VERSION > /dev/null 2>&1; then
+  # Use a lock file to avoid concurrent installations (for colocated jobs).
+  # Skip locking if /var/vcap/sys/run isn't available (e.g., dedicated errand VMs).
+  BUNDLER_LOCK_FILE="/var/vcap/sys/run/bundler_install.lock"
+  if [[ -d "$(dirname $BUNDLER_LOCK_FILE)" ]]; then
+    (
+      flock -x 200
+      if ! gem list -i bundler -v $BUNDLER_VERSION > /dev/null 2>&1; then
+        gem install --local ${CC_PACKAGE_DIR}/cloud_controller_ng/vendor/cache/bundler-${BUNDLER_VERSION}.gem
+      fi
+    ) 200>$BUNDLER_LOCK_FILE
+  else
     gem install --local ${CC_PACKAGE_DIR}/cloud_controller_ng/vendor/cache/bundler-${BUNDLER_VERSION}.gem
   fi
-) 200>$BUNDLER_LOCK_FILE
+fi