Update git submodules

* Update docs/submodules/releng/builder from branch 'master'
  to b1b8801f1eaa12f26aab29fb7245d0475ee12ec1
  - Merge "Fail if image delete does not succeed"
  - Fail if image delete does not succeed

    by ignoring the delte failure, we can end up
    creating images with duplicate names which confuse
    heat when trying to deploy stacks with images using
    those names.

    a delete can fail if an image is being used when
    the delete is issued.

    Change-Id: Iff82bd566d573cb2535236f46de9d7cb44c6aa4c
    Signed-off-by: Jamo Luhrsen <jluhrsen@redhat.com>

diff --git a/docs/submodules/releng/builder b/docs/submodules/releng/builder
index 240756b41a78658792ad3e940526acda499ef96a..b1b8801f1eaa12f26aab29fb7245d0475ee12ec1 160000 (submodule)
--- a/docs/submodules/releng/builder
+++ b/docs/submodules/releng/builder
@@ -1 +1 @@
-Subproject commit 240756b41a78658792ad3e940526acda499ef96a
+Subproject commit b1b8801f1eaa12f26aab29fb7245d0475ee12ec1