Remove platform/external/sil-fonts

BUG:17508191
Change-Id: I7bc7dc244e5f5839630395bef4104a102428a667

default.xml

@@ -231,7 +231,6 @@
   <project path="external/scrypt" name="platform/external/scrypt" groups="pdk" />
   <project path="external/sepolicy" name="platform/external/sepolicy" groups="pdk" />
   <project path="external/sfntly" name="platform/external/sfntly" />
-  <project path="external/sil-fonts" name="platform/external/sil-fonts" />
   <project path="external/skia" name="platform/external/skia" />
   <project path="external/smack" name="platform/external/smack" />
   <project path="external/smali" name="platform/external/smali" />