mail/spamassassin: Fix command_interpreter regression

PR/196517, the rc script unable to find its .pid file, has returned.
Restore SVN r376379 (691102663f), fixing this bug again.

PR:		196517
Reported by:	ler

mail/spamassassin/Makefile

@@ -1,5 +1,6 @@
 PORTNAME=	spamassassin
 PORTVERSION=	4.0.0
+PORTREVISION=	1
 CATEGORIES?=	mail perl5
 MASTER_SITES=	https://archive.apache.org/dist/${PORTNAME}/source/ CPAN/Mail
 DISTNAME=	Mail-SpamAssassin-${PORTVERSION}

mail/spamassassin/files/sa-spamd.in

@@ -40,7 +40,6 @@ restart_precmd="precmd"
 pidfile=${spamd_pidfile:-"/var/run/${name}/${name}.pid"}
 command=%%PREFIX%%/bin/${name}
 command_args="-d -r ${pidfile}"
-command_interpreter="%%PREFIX%%/bin/perl"
 required_dirs="%%PREFIX%%/share/spamassassin"
 
 precmd()