Remove libweave repository.

This is a client interface for a daemon that we are not including in
the manifest anyway.
Bug: None
Test: `make checkbuild` doesn't complain about it not being there.
Change-Id: Ieadfc096ad38ca88f17c436e13fa6d7850280698

default.xml

@@ -230,7 +230,6 @@
   <project path="external/libvorbis" name="platform/external/libvorbis" groups="pdk" />
   <project path="external/libvpx" name="platform/external/libvpx" groups="pdk" />
   <project path="external/libvterm" name="platform/external/libvterm" groups="pdk" />
-  <project path="external/libweave" name="platform/external/libweave" groups="pdk" />
   <project path="external/libxml2" name="platform/external/libxml2" groups="pdk,libxml2" />
   <project path="external/libyuv" name="platform/external/libyuv" groups="pdk,libyuv" />
   <project path="external/linux-kselftest" name="platform/external/linux-kselftest" groups="vts,pdk" />