Check and create plugins dir before copying plugins

Also restore missing plugin installing

PROD-36733

Change-Id: I10164834af2c66d12e53b60fc28266354a9c3d2d
diff --git a/pre_startup_copy_plugins.sh b/pre_startup_copy_plugins.sh
index a6b2338..5e19bca 100644
--- a/pre_startup_copy_plugins.sh
+++ b/pre_startup_copy_plugins.sh
@@ -5,6 +5,9 @@
 # The script will watch "$JENKINS_HOME/.plugins_for_X.XXX.X_installed" file existence.
 set -e
 watchfile="${JENKINS_HOME}/.plugins_for_2.263.4_installed"
+
+test -d "${JENKINS_HOME}/plugins" || mkdir -p "${JENKINS_HOME}/plugins"
+
 if [[ ! -f "${watchfile}" ]] ; then
   cp /opt/plugins_files_offline/*.jpi "${JENKINS_HOME}/plugins"
   touch "${watchfile}"