pkg: switch release to OpenVPN 2.4 and fixed PHP version

(cherry picked from commit d0d52b08)

Makefile

@@ -44,7 +44,7 @@ CORE_HASH=	${CORE_COMMIT:C/^.*-//1}
 CORE_ABI?=	17.1
 CORE_ARCH?=	${ARCH}
 CORE_BIND?=	911
-CORE_OPENVPN?=	23
+CORE_OPENVPN?=	# empty for version 2.4
 CORE_PHP?=	70
 CORE_PY?=	27
 
@@ -97,9 +97,9 @@ CORE_DEPENDS?=		apinger \
 			opnsense-lang \
 			opnsense-update \
 			pam_opnsense \
-			pecl-radius \
+			pecl-radius${CORE_PHP} \
 			pftop \
-			phalcon \
+			phalcon${CORE_PHP} \
 			php${CORE_PHP}-ctype \
 			php${CORE_PHP}-curl \
 			php${CORE_PHP}-dom \