Revert "Update felix SVN to  21"

This reverts commit 29203a354d62370c5bd4e6e92592a00eead176e6.

Reason for revert: b/289414927
Bug: 289414927
Change-Id: I37230a6d768bd2293b7c9fb4bf9659b9a31f5ae8
diff --git a/device-felix.mk b/device-felix.mk
index c25c2e2..86f55cd 100644
--- a/device-felix.mk
+++ b/device-felix.mk
@@ -205,7 +205,7 @@
 
 # Increment the SVN for any official public releases
 PRODUCT_VENDOR_PROPERTIES += \
-    ro.vendor.build.svn=21
+    ro.vendor.build.svn=20
 
 # Vibrator HAL
 PRODUCT_VENDOR_PROPERTIES +=\