Build OPA dependencies only if OPA plugin is enabled

dependencies.mk

@@ -61,7 +61,7 @@ FETCH = wget -c --no-check-certificate -O
 MD5 = $(if $(shell which md5 2>/dev/null),md5,$(if $(shell md5sum --tag Makefile 2&> /dev/null || true),md5sum --tag,openssl md5))
 DISTFILESNAMES = $(foreach f,$(DISTFILES),$(shell echo "$(f)" | sed 's/;.*//'))
 DISTFILESPATHS_FULL = $(foreach f,$(DISTFILES),$(shell echo "$(f)" | sed 's/.tar.gz;.*//; s/.tgz;.*//; s/.zip;.*//' ))
-DISTFILESPATHS = apache-cassandra-$(CASSANDRA_VERSION) mosquitto-$(MOSQUITTO_VERSION) boost_$(BOOST_VERSION_U) openssl-$(OPENSSL_VERSION) libuv-v$(LIBUV_VERSION) cpp-driver-$(CPPDRV_VERSION) opencv-$(OPENCV_VERSION) mariadb-connector-c-$(MARIADBCONNECTOR_VERSION)-src IntelOPA-Basic.SLES124-x86_64.$(OPASTACK_VERSION)
+DISTFILESPATHS = apache-cassandra-$(CASSANDRA_VERSION) mosquitto-$(MOSQUITTO_VERSION) boost_$(BOOST_VERSION_U) openssl-$(OPENSSL_VERSION) libuv-v$(LIBUV_VERSION) cpp-driver-$(CPPDRV_VERSION) opencv-$(OPENCV_VERSION) mariadb-connector-c-$(MARIADBCONNECTOR_VERSION)-src
 ifneq (,$(findstring bacnet,$(PLUGINS)))
  	DISTFILESPATHS += bacnet-stack-$(BACNET-STACK_VERSION) 
 endif
@@ -71,6 +71,9 @@ endif
 ifneq (,$(findstring snmp,$(PLUGINS)))
  	DISTFILESPATHS += net-snmp-$(NET-SNMP_VERSION) 
 endif
+ifneq (,$(findstring opa,$(PLUGINS)))
+        DISTFILESPATHS += IntelOPA-Basic.SLES124-x86_64.$(OPASTACK_VERSION)
+endif
 
 
 # If cross-compiling for ARM, adjust the build settings