xbps-src: return early if masterdir is not ready for chroot ops.

common/xbps-src/shutils/chroot.sh

@@ -155,6 +155,9 @@ chroot_sync_repos() {
 chroot_handler() {
     local action="$1" pkg="$2" rv=0 arg= _envargs= _chargs=
 
+    if [ -z "$CHROOT_READY" ]; then
+        return 0
+    fi
     # Debian uses /run/shm instead...
     if [ -d /run/shm ]; then
         mkdir -p ${XBPS_MASTERDIR}/run/shm