Remove lldb from the manifest

This branch of the project has not been touched for 2 years and I
am not aware of anyone using it. All LLDB development is now going
on in the lldb-master-dev branch.

Change-Id: Ibb2dc1c940f52ac14faec57e283272a002183537

default.xml

@@ -218,7 +218,6 @@
   <project path="external/libyuv" name="platform/external/libyuv" groups="libyuv,pdk-cw-fs,pdk-fs" />
   <project path="external/littlemock" name="platform/external/littlemock" groups="pdk-cw-fs,pdk-fs" />
   <project path="external/lld" name="platform/external/lld" groups="pdk-fs" />
-  <project path="external/lldb" name="platform/external/lldb" groups="pdk-cw-fs,pdk-fs" />
   <project path="external/llvm" name="platform/external/llvm" groups="pdk" />
   <project path="external/ltrace" name="platform/external/ltrace" groups="pdk-cw-fs,pdk-fs" />
   <project path="external/lz4" name="platform/external/lz4" groups="pdk-cw-fs,pdk-fs" />