Update git submodules

* Update os-api-ref from branch 'master'
  to 0b802f4ae8ffd34da3b162a3fccd7f2b0181739c
  - Drop workaround for python < 2.7.4

    Change-Id: I94e2d2d393e7add0a3ff2bf17d254cf2e1766bc0
    Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

diff --git a/os-api-ref b/os-api-ref
index 53226f8a6759414e51cba04927f789937673ed05..0b802f4ae8ffd34da3b162a3fccd7f2b0181739c 160000 (submodule)
--- a/os-api-ref
+++ b/os-api-ref
@@ -1 +1 @@
-Subproject commit 53226f8a6759414e51cba04927f789937673ed05
+Subproject commit 0b802f4ae8ffd34da3b162a3fccd7f2b0181739c