Simplify selection of the address to publish for a given BTL TCP
module in the module exchange code. Rather than looping through
all IP addresses associated with a node, looking for one that
matches the kindex of a module, loop over the modules and
use the address stored in the module structure. This also
happens to be the address that the source will use to bind()
in a connect() call, so this should eliminate any confusion
(read: bugs) when an interface has multiple IPs associated with
it.
Refs #5818
Signed-off-by: Brian Barrett <bbarrett@amazon.com>