Store log files from pbuilder in $PRODUCT_OUT

Change-Id: I3fa23ef954092f346cbd0d787867359ddce0528d
diff --git a/packages.mk b/packages.mk
index a4e3da6..51b5508 100644
--- a/packages.mk
+++ b/packages.mk
@@ -70,7 +70,7 @@
 		--basetgz $(ROOTDIR)/cache/base.tgz \
 		--configfile $(ROOTDIR)/build/pbuilderrc \
 		--hookdir $(ROOTDIR)/build/pbuilder-hooks \
-		--host-arch arm64
+		--host-arch arm64 --logfile $(PRODUCT_OUT)/$1.log
 else
 $(PRODUCT_OUT)/.$1-pbuilder: \
 	| out-dirs \