Deps: stop setting archs for each source

Multiple options confuse apt, and with a recent apt update, setting trusted=yes
on one source entry and leaving it off of another causes a validation failure.
Instead, set the architectures using `dpkg --add-architecture`.

Change-Id: Ie6cf5637f79c3d74d45c3fce1f4913bf4ce98aa7
diff --git a/pbuilder-hooks/D05deps b/pbuilder-hooks/D05deps
index c2c8307..b9cf71d 100755
--- a/pbuilder-hooks/D05deps
+++ b/pbuilder-hooks/D05deps
@@ -1,8 +1,9 @@
 #!/bin/bash -xe
 sed -i '/^deb http:/ s/$/ contrib non-free/' /etc/apt/sources.list
 echo "deb [trusted=yes] file://$DEPSBASE ./" >> /etc/apt/sources.list
-echo "deb [arch=arm64] http://packages.cloud.google.com/apt mendel-bsp-$BOARD_NAME-day main" >> /etc/apt/sources.list
+echo "deb [trusted=yes] http://packages.cloud.google.com/apt mendel-bsp-$BOARD_NAME-day main" >> /etc/apt/sources.list
 echo "deb [arch=amd64] http://storage.googleapis.com/bazel-apt stable jdk1.8" >> /etc/apt/sources.list
+
 echo 'Debug::pkgProblemResolver true;' > /etc/apt/apt.conf
 
 install -D -m 644 -o root -g root \
@@ -15,4 +16,6 @@
 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 -
+dpkg --add-architecture arm64
+dpkg --add-architecture amd64
 apt-get update || true