Update init scripts to use "test config" subcommand (elastic#4797)

Using "-configtest" is deprecated and the "[beat] test config" subcommand should be used instead.

Fixes elastic#4600

CHANGELOG.asciidoc

@@ -57,6 +57,8 @@ https://github.com/elastic/beats/compare/v6.0.0-beta1...master[Check the HEAD di
 
 *Affecting all Beats*
 
+- Update init scripts to use the `test config` subcommand instead of the deprecated `-configtest` flag. {issue}4600[4600]
+
 *Auditbeat*
 
 - Added `file.hash_types` config option for controlling the hash types. {pull}4796[4796]

dev-tools/packer/platforms/centos/init.j2

@@ -26,7 +26,7 @@ export PATH
 pidfile=${PIDFILE-/var/run/{{.beat_pkg_name}}.pid}
 agent=${BEATS_AGENT-/usr/share/{{.beat_name}}/bin/{{.beat_name}}}
 args="-c /etc/{{.beat_name}}/{{.beat_name}}.yml -path.home /usr/share/{{.beat_name}} -path.config /etc/{{.beat_name}} -path.data /var/lib/{{.beat_name}} -path.logs /var/log/{{.beat_name}}"
-test_args="-e -configtest"
+test_args="-e test config"
 beat_user="${BEAT_USER:-root}"
 wrapper="/usr/share/{{.beat_name}}/bin/{{.beat_name}}-god"
 wrapperopts="-r / -n -p $pidfile"

dev-tools/packer/platforms/debian/init.j2

@@ -18,7 +18,7 @@ DESC="{{.beat_description}}"
 NAME="{{.beat_name}}"
 DAEMON=/usr/share/{{.beat_name}}/bin/$NAME
 DAEMON_ARGS="-c /etc/{{.beat_name}}/{{.beat_name}}.yml -path.home /usr/share/{{.beat_name}} -path.config /etc/{{.beat_name}} -path.data /var/lib/{{.beat_name}} -path.logs /var/log/{{.beat_name}}"
-TEST_ARGS="-e -configtest"
+TEST_ARGS="-e test config"
 PIDFILE=/var/run/{{.beat_pkg_name}}.pid
 WRAPPER="/usr/share/{{.beat_name}}/bin/{{.beat_name}}-god"
 BEAT_USER="root"