Make change and version bump to OPR4.170623.020

Change-Id: I7ca6ec80deee5548a670db3d5d0cad250635ef8f
diff --git a/core/build_id.mk b/core/build_id.mk
index a8caf4e..a53de91 100644
--- a/core/build_id.mk
+++ b/core/build_id.mk
@@ -18,4 +18,4 @@
 # (like "CRB01").  It must be a single word, and is
 # capitalized by convention.
 
-export BUILD_ID=OPR4.170623.019
+export BUILD_ID=OPR4.170623.020
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 636d9e3..420d8b1 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -165,7 +165,7 @@
     #  It must be of the form "YYYY-MM-DD" on production devices.
     #  It must match one of the Android Security Patch Level strings of the Public Security Bulletins.
     #  If there is no $PLATFORM_SECURITY_PATCH set, keep it empty.
-      PLATFORM_SECURITY_PATCH := 2017-11-06
+      PLATFORM_SECURITY_PATCH := 2017-12-01
 endif
 
 ifndef PLATFORM_BASE_OS