Remove CONF_FILE check

This commit removes a legacy check for an unsupported environment
variable. This environment variable has not been supported since 1.x so
it is safe to stop checking for the existence of this setting.

Relates elastic/x-pack-elasticsearch#2048

Original commit: elastic/x-pack-elasticsearch@023230fa9e

plugin/bin/x-pack/certgen

@@ -66,12 +66,6 @@ if [ "x$JAVA_TOOL_OPTIONS" != "x" ]; then
     unset JAVA_TOOL_OPTIONS
 fi
 
-# CONF_FILE setting was removed
-if [ ! -z "$CONF_FILE" ]; then
-    echo "CONF_FILE setting is no longer supported. elasticsearch.yml must be placed in the config directory and cannot be renamed."
-    exit 1
-fi
-
 declare -a args=("$@")
 
 if [ -e "$CONF_DIR" ]; then

plugin/bin/x-pack/croneval

@@ -66,12 +66,6 @@ if [ "x$JAVA_TOOL_OPTIONS" != "x" ]; then
     unset JAVA_TOOL_OPTIONS
 fi
 
-# CONF_FILE setting was removed
-if [ ! -z "$CONF_FILE" ]; then
-    echo "CONF_FILE setting is no longer supported. elasticsearch.yml must be placed in the config directory and cannot be renamed."
-    exit 1
-fi
-
 declare -a args=("$@")
 
 if [ -e "$CONF_DIR" ]; then

plugin/bin/x-pack/extension

@@ -56,12 +56,6 @@ fi
 # include x-pack jars in classpath
 ES_CLASSPATH="$ES_CLASSPATH:$ES_HOME/plugins/x-pack/*"
 
-# CONF_FILE setting was removed
-if [ ! -z "$CONF_FILE" ]; then
-    echo "CONF_FILE setting is no longer supported. elasticsearch.yml must be placed in the config directory and cannot be renamed."
-    exit 1
-fi
-
 declare -a args=("$@")
 
 if [ -e "$CONF_DIR" ]; then

plugin/bin/x-pack/migrate

@@ -66,12 +66,6 @@ if [ "x$JAVA_TOOL_OPTIONS" != "x" ]; then
     unset JAVA_TOOL_OPTIONS
 fi
 
-# CONF_FILE setting was removed
-if [ ! -z "$CONF_FILE" ]; then
-    echo "CONF_FILE setting is no longer supported. elasticsearch.yml must be placed in the config directory and cannot be renamed."
-    exit 1
-fi
-
 declare -a args=("$@")
 
 if [ -e "$CONF_DIR" ]; then

plugin/bin/x-pack/setup-passwords

@@ -66,12 +66,6 @@ if [ "x$JAVA_TOOL_OPTIONS" != "x" ]; then
     unset JAVA_TOOL_OPTIONS
 fi
 
-# CONF_FILE setting was removed
-if [ ! -z "$CONF_FILE" ]; then
-    echo "CONF_FILE setting is no longer supported. elasticsearch.yml must be placed in the config directory and cannot be renamed."
-    exit 1
-fi
-
 declare -a args=("$@")
 
 if [ -e "$CONF_DIR" ]; then

plugin/bin/x-pack/syskeygen

@@ -66,12 +66,6 @@ if [ "x$JAVA_TOOL_OPTIONS" != "x" ]; then
     unset JAVA_TOOL_OPTIONS
 fi
 
-# CONF_FILE setting was removed
-if [ ! -z "$CONF_FILE" ]; then
-    echo "CONF_FILE setting is no longer supported. elasticsearch.yml must be placed in the config directory and cannot be renamed."
-    exit 1
-fi
-
 declare -a args=("$@")
 
 if [ -e "$CONF_DIR" ]; then

plugin/bin/x-pack/users

@@ -66,12 +66,6 @@ if [ "x$JAVA_TOOL_OPTIONS" != "x" ]; then
     unset JAVA_TOOL_OPTIONS
 fi
 
-# CONF_FILE setting was removed
-if [ ! -z "$CONF_FILE" ]; then
-    echo "CONF_FILE setting is no longer supported. elasticsearch.yml must be placed in the config directory and cannot be renamed."
-    exit 1
-fi
-
 declare -a args=("$@")
 
 if [ -e "$CONF_DIR" ]; then