Fixed Opcache Debian 6 issue

src/modules/stack/install/ee_mod_setup_php.sh

@@ -68,11 +68,13 @@ function ee_mod_setup_php()
 		mv /usr/share/GeoIP/GeoLiteCity.dat /usr/share/GeoIP/GeoIPCity.dat
 
 		# Setup Zend OpCache as per RAM
+		if [ -f /etc/php5/fpm/conf.d/05-opcache.ini ]; then
 			grep memory_consumption /etc/php5/fpm/conf.d/05-opcache.ini &> /dev/null 
 			if [ $? -ne 0 ]; then
 				sed -i "s/zend_extension=opcache.so/zend_extension=opcache.so\nopcache.memory_consumption=${EE_OPCACHE_SIZE}\nopcache.max_accelerated_files=50000/" /etc/php5/fpm/conf.d/05-opcache.ini \
 				|| ee_lib_error "Unable to change opcache.memory_consumption, exit status = " $?
 			fi
+		fi
 
 		# Setup PHP Memcache as per RAM
 		sed -i "s/-m.*/-m ${EE_MEMCACHE_SIZE}/" /etc/memcached.conf \