Update Crosshatch SVN to 4 for January 2019 release
bug:118903919
(cherry picked from commit 5abdc7455cf70750fda4d0a48f711e69e098e681)

Change-Id: I0877d1997752e406951116d2d59c818e0c81880a
diff --git a/device.mk b/device.mk
index 1dfc2bc..f0d48bb 100644
--- a/device.mk
+++ b/device.mk
@@ -790,4 +790,4 @@
 
 # Increment the SVN for any official public releases
 PRODUCT_PROPERTY_OVERRIDES += \
-    ro.vendor.build.svn=3
+    ro.vendor.build.svn=4