Re-add marisa-trie depencency as it is used internally.

Fixes dalvik-dev branch.
diff --git a/default.xml b/default.xml
index efd1d3c..bbbfe5d 100644
--- a/default.xml
+++ b/default.xml
@@ -223,6 +223,7 @@
   <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" />
   <project path="external/lzma" name="platform/external/lzma" groups="pdk" />
+  <project path="external/marisa-trie" name="platform/external/marisa-trie" groups="pdk-cw-fs,pdk-fs" />
   <project path="external/markdown" name="platform/external/markdown" groups="pdk-cw-fs,pdk-fs" />
   <project path="external/mdnsresponder" name="platform/external/mdnsresponder" groups="pdk" />
   <project path="external/mesa3d" name="platform/external/mesa3d" groups="pdk-cw-fs,pdk-fs" />