Cirrus: Try apt-get twice

We were seeing some intermitttent failures here.

tools/cirrus_build_project.sh

@@ -16,7 +16,8 @@ lscpu
 free -m
 
 echo "Installing rbm deps..."
-apt-get install -y libyaml-libyaml-perl libtemplate-perl libio-handle-util-perl libio-all-perl libio-captureoutput-perl libjson-perl libpath-tiny-perl libstring-shellquote-perl libsort-versions-perl libdigest-sha-perl libdata-uuid-perl libdata-dump-perl libfile-copy-recursive-perl libfile-slurp-perl git runc
+APT_DEPS="libyaml-libyaml-perl libtemplate-perl libio-handle-util-perl libio-all-perl libio-captureoutput-perl libjson-perl libpath-tiny-perl libstring-shellquote-perl libsort-versions-perl libdigest-sha-perl libdata-uuid-perl libdata-dump-perl libfile-copy-recursive-perl libfile-slurp-perl git runc"
+apt-get install -y $APT_DEPS || (sleep 15s && apt-get install -y $APT_DEPS)
 
 echo "Pulling rbm..."
 make submodule-update