Remove abi/cpp from the manifest

libgabi++ from abi/cpp was only useful with stlport and libstdc++,
neither of which is used in the platform any more.  The NDK has its own
copy of libgabi++, so remove the platform version.

Change-Id: I3c97a5e49c8b0e9d1269567e0c16da8b5df604aa
(cherry picked from commit aa1c5ac067a8ae8050aeb0ad0befdfbfbdddf9ea)
diff --git a/default.xml b/default.xml
index f8a83d7..28116fe 100644
--- a/default.xml
+++ b/default.xml
@@ -30,7 +30,6 @@
     <linkfile src="root.bp" dest="Android.bp" />
     <linkfile src="bootstrap.bash" dest="bootstrap.bash" />
-  <project path="abi/cpp" name="platform/abi/cpp" groups="bdk" />
   <project path="bionic" name="platform/bionic" groups="bdk" />
   <project path="bootable/recovery" name="platform/bootable/recovery" groups="bdk" />
   <project path="device/generic/arm64" name="device/generic/arm64" groups="bdk" />