Update git submodules

* Update docs/submodules/releng/builder from branch 'master'
  to 15f058c91204bcb6847903a34f2a0411661ad5f1
  - Dump server console logs on failure

    Need this to helps us troubleshoot the issue mentioned in the
    metadata string.

    Issue: https://jira.linuxfoundation.org/browse/RELENG-1057
    Change-Id: I35939c44795089f071b728a26283c8b798ad7dff
    Signed-off-by: Thanh Ha <thanh.ha@linuxfoundation.org>

diff --git a/docs/submodules/releng/builder b/docs/submodules/releng/builder
index 775681ade6528b86b24fb2b3a3a1f9d11299f419..15f058c91204bcb6847903a34f2a0411661ad5f1 160000 (submodule)
--- a/docs/submodules/releng/builder
+++ b/docs/submodules/releng/builder
@@ -1 +1 @@
-Subproject commit 775681ade6528b86b24fb2b3a3a1f9d11299f419
+Subproject commit 15f058c91204bcb6847903a34f2a0411661ad5f1