Fix 500 error on retrieving metadata by invalid URI

An invalid URI should return a BadRequest error rather
than making the metadata proxy bomb out.

Closes-bug: #1371160

Change-Id: Ifb495f9e8929062a0c24d090c3e702109a38803a
Fix KeyError when getting secgroup info for ports

The patch fixes a regression introduced with secgroup rpc refactor by
handling the case when security group contains rules for only IPv4 or
IPv6.

Change-Id: I02b174757bfc796a81cdb482c55ba7f9e954131d
Closes-bug: #1372337
Merge "Fix KeyError when getting secgroup info for ports"
Merge "Fix 500 error on retrieving metadata by invalid URI"