The builders project is gone. Remove it from main.mk

Change-Id: Ibec7be55667e83d635e1de990772e2730d0e75ff
diff --git a/core/main.mk b/core/main.mk
index 24ac676..688ad9d 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -398,7 +398,6 @@
 	sdk/layoutlib_utils \
 	sdk/ninepatch \
 	sdk/sdkstats \
-	sdk/builders \
 	sdk/sdkmanager \
 	sdk/layoutopt \
 	development/apps \