Revert "Replace Launcher2 with Launcher3"

Bug: 21164174

This reverts commit d79778faf3180ec0db67e7a12e0871d39867565a.

Change-Id: Ide6b2dc4c511a60bcdf22dd44369e3a9fa08d1af
diff --git a/target/product/core.mk b/target/product/core.mk
index d27fb8e..519dbb8 100644
--- a/target/product/core.mk
+++ b/target/product/core.mk
@@ -40,7 +40,7 @@
     KeyChain \
     Keyguard \
     LatinIME \
-    Launcher3 \
+    Launcher2 \
     ManagedProvisioning \
     PicoTts \
     PacProcessor \