Dockerfile: Add default SSH config

* Add a default ssh config that won't blow up due to empty/missing
  known_hosts file.
* Those concerned about security are expected to fork the repo and
  update the Dockerfile to include trusted values.

Dockerfile

@@ -27,6 +27,7 @@ RUN chmod 755 /usr/local/bin/*
 # All builds will be done by user aosp
 RUN useradd --create-home aosp
 ADD gitconfig /home/aosp/.gitconfig
+ADD ssh_config /home/aosp/.ssh/config
 RUN chown aosp:aosp /home/aosp/.gitconfig
 
 # The persistent data will be in these two directories, everything else is

ssh_config

@@ -0,0 +1,4 @@
+# Somewhat insecure, fork and override as needed.
+Host *
+	#IdentityFile /root/.ssh/id_rsa
+	StrictHostKeyChecking no