Revert "Turn CONFIG_AMVR on by default"

This reverts commit 083be6aab77041b96391c7a1a021a6b6fd946d98.

Reason for revert: AMVR causes a segmentation fault when encoding

BUG=aomedia:1466

Change-Id: I6c835629a17bfbebe34caaad40a2524689246cdb
diff --git a/build/cmake/aom_config_defaults.cmake b/build/cmake/aom_config_defaults.cmake
index a911285..04a4317 100644
--- a/build/cmake/aom_config_defaults.cmake
+++ b/build/cmake/aom_config_defaults.cmake
@@ -87,7 +87,7 @@
 set(CONFIG_SPATIAL_RESAMPLING 1 CACHE NUMBER "Spatial resampling.")
 
 # AV1 experiment flags.
-set(CONFIG_AMVR 1 CACHE NUMBER "AV1 experiment flag.")
+set(CONFIG_AMVR 0 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_AOM_QM_EXT 1 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_CDF_UPDATE_MODE 0 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_CFL 1 CACHE NUMBER "AV1 experiment flag.")