Vault < 0.6.2 errors out if the development server listen address is set

when not running in dev mode; this means that the fix for #2 cause it to
be very difficult to run not in dev mode (basically requiring your own
entrypoint). This fixes that issue with a check that can be removed for
0.6.2+.

library/vault

@@ -1,6 +1,6 @@
 # maintainer: Jeff Mitchell <[email protected]> (@jefferai)
 
-0.6.0: git://github.com/hashicorp/docker-vault@296309e4e40be197e89b9f063463fe02c4c5c3e2 0.6
-0.6: git://github.com/hashicorp/docker-vault@296309e4e40be197e89b9f063463fe02c4c5c3e2 0.6.1
-0.6.1: git://github.com/hashicorp/docker-vault@296309e4e40be197e89b9f063463fe02c4c5c3e2 0.6.1
-latest: git://github.com/hashicorp/docker-vault@296309e4e40be197e89b9f063463fe02c4c5c3e2 0.6.1
+0.6.0: git://github.com/hashicorp/docker-vault@7c54a44d323e4fe01ba6a83c7d731902b5b96e5b 0.6
+0.6: git://github.com/hashicorp/docker-vault@7c54a44d323e4fe01ba6a83c7d731902b5b96e5b 0.6.1
+0.6.1: git://github.com/hashicorp/docker-vault@7c54a44d323e4fe01ba6a83c7d731902b5b96e5b 0.6.1
+latest: git://github.com/hashicorp/docker-vault@7c54a44d323e4fe01ba6a83c7d731902b5b96e5b 0.6.1