pbuilder: Update to build from public apt repositories

This adjusts the build to pull packages from the public Mendel apt repositories
during builds.

Change-Id: If55ffa86b5fed0b0df0305ecf2cca3ca1a227369
diff --git a/packages.mk b/packages.mk
index 71afe4e..fb69abe 100644
--- a/packages.mk
+++ b/packages.mk
@@ -28,7 +28,7 @@
 	mkdir -p $(ROOTDIR)/cache
 	sudo pbuilder create \
 		--basetgz $@ \
-		--mirror http://ftp.debian.org/debian \
+		--othermirror "deb http://packages.cloud.google.com/apt mendel-chef main|deb http://packages.cloud.google.com/apt mendel-bsp-$(BOARD_NAME)-chef main" \
 		--distribution stretch \
 		--architecture amd64 \
 		--extrapackages "crossbuild-essential-armhf crossbuild-essential-arm64 debhelper gnupg lintian"
diff --git a/pbuilder-hooks/D05deps b/pbuilder-hooks/D05deps
index 3c53c60..3e02eb2 100755
--- a/pbuilder-hooks/D05deps
+++ b/pbuilder-hooks/D05deps
@@ -5,4 +5,6 @@
 echo 'Debug::pkgProblemResolver true;' > /etc/apt/apt.conf
 cp -r /rootdir/build/lintian /usr/share/
 cat /rootdir/build/bazel-release.pub.gpg | apt-key add -
+cat /rootdir/packages/mendel-keyring/cloud-key.gpg | apt-key add -
+cat /rootdir/packages/mendel-keyring/linux_signing_key.pub |apt-key add -
 apt-get update
diff --git a/pbuilderrc b/pbuilderrc
index 261e7be..ac54eda 100644
--- a/pbuilderrc
+++ b/pbuilderrc
@@ -4,7 +4,7 @@
 # the default template
 #
 # read pbuilderrc.5 document for notes on specific options.
-MIRRORSITE=http://ftp.debian.org/debian
+OTHERMIRROR="deb https://packages.cloud.google.com/apt mendel-chef main|deb https://packages.cloud.google.com/apt mendel-bsp-$BOARD_NAME-chef main"
 PBUILDERSATISFYDEPENDSCMD=/usr/lib/pbuilder/pbuilder-satisfydepends-apt
 export DEPSBASE=$PRODUCT_OUT/packages
 BINDMOUNTS="$DEPSBASE $ROOTDIR"