O MR1 is API 27

Bug: 64982450
Test: manual
Change-Id: I0d59724f1bcb8091488f23cd5d98d2688009b605
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index f0e7f84..1e2611a 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -105,7 +105,7 @@
   # When you increment the PLATFORM_SDK_VERSION please ensure you also
   # clear out the following text file of all older PLATFORM_VERSION's:
   # cts/tests/tests/os/assets/platform_versions.txt
-  PLATFORM_SDK_VERSION := 26
+  PLATFORM_SDK_VERSION := 27
 endif
 
 ifndef PLATFORM_JACK_MIN_SDK_VERSION