Enable filter_7bit by default

Change-Id: Ic587cddf04053bced6325b3cd5ce1b963e783393

configure

diff --git a/configure b/configure
index c51d075..5b622d7 100755
--- a/configure
+++ b/configure
@@ -461,6 +461,9 @@
     # Enable ref_mv by default
     soft_enable ref_mv
 
+    # Enable filter_7bit by default
+    soft_enable filter_7bit
+
     # Enable daala_ec by default
     ! enabled ans && soft_enable daala_ec