Fixed minor typo leading to double-slashes.

build-rootfs.sh

@@ -8,7 +8,7 @@ CHECK_GPG=false
 CLEAN_INTERMEDIATES=false
 CONTAINER_VOLUME_CONFIG=/var/roundcube/config
 CONTAINER_WEBROOT=/var/www/html
-CONTAINER_PHP_CONFD=/usr/local/etc/php/conf.d/
+CONTAINER_PHP_CONFD=/usr/local/etc/php/conf.d
 CONTAINER_SCRIPTS=/usr/local/sbin
 
 # This is internal stuff used to build everything