Only download ghost if needed

src/freedombone-app-ghost

@@ -396,7 +396,9 @@ function install_ghost {
         mkdir -p /var/www/$GHOST_DOMAIN_NAME/htdocs
     fi
     cd /var/www/$GHOST_DOMAIN_NAME/htdocs
-    wget ${GHOST_DOWNLOAD_URL}
+    if [ ! -f Ghost-${GHOST_VERSION}.zip ]; then
+        wget ${GHOST_DOWNLOAD_URL}
+    fi
     if [ ! -f Ghost-${GHOST_VERSION}.zip ]; then
         echo $'Unable to download ghost'
         rm -rf /var/www/$GHOST_DOMAIN_NAME