remove deprecated MAX_THREADS option

This option doesn't seem to exists anymore in elasticsearch. It's not present in current versions of system configuration provided by recent elasticsearch packages and there is no code using it inside elasticsearch.

README.md

@@ -405,7 +405,6 @@ In addition to es_config, the following parameters allow the customization of th
 * ```update_java``` Updates Java to the latest version. (true or false (default))
 * ```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.
 * ```es_use_repository``` Setting this to `false` will stop Ansible from using the official Elastic package from any repository configured on the system.
 * ```es_add_repository``` Setting this to `false` will stop Ansible to add the official Elastic package repositories (if es_use_repository is true) if you want to use a repo already present.

defaults/main.yml

@@ -28,7 +28,6 @@ es_data_dirs:
 es_log_dir: "/var/log/elasticsearch"
 es_action_auto_create_index: true
 es_max_open_files: 65536
-es_max_threads: 8192
 es_max_map_count: 262144
 es_allow_downgrades: false
 es_xpack_features: []

templates/elasticsearch.j2

@@ -66,8 +66,3 @@ MAX_LOCKED_MEMORY=unlimited
 MAX_MAP_COUNT={{es_max_map_count}}
 {% endif %}
 
-# Specifies the maximum number of threads that can be started.
-# Elasticsearch requires a minimum of 2048.
-{% if es_max_threads is defined %}
-MAX_THREADS={{ es_max_threads }}
-{% endif %}