Documentation update

README.md

@@ -348,6 +348,7 @@ In addition to es_config, the following parameters allow the customization of th
 * ```es_max_map_count``` maximum number of VMA (Virtual Memory Areas) a process can own. Defaults to 262144.
 * ```es_max_open_files``` the maximum file descriptor number that can be opened by this process. Defaults to 65536.
 * ```es_max_threads``` the maximum number of threads the process can start. Defaults to 2048 (the minimum required by elasticsearch).
+* ```es_debian_startup_timeout``` how long Debian-family SysV init scripts wait for the service to start, in seconds. Defaults to 10 seconds.
 
 Earlier examples illustrate the installation of plugins using `es_plugins`.  For officially supported plugins no version or source delimiter is required. The plugin script will determine the appropriate plugin version based on the target Elasticsearch version.  For community based plugins include the full url.  This approach should NOT be used for the X-Pack plugin.  See X-Pack below for details here.