Fix dangling references.

Now that we've backed out the premature push, reapply the actual fix to
propagate it appropriately.

This changeset was prematurely pushed to the wrong repository. Back it out
to propagate it the right way.

llhttpclient_test.cpp is only supposed to be run by test_llsdmessage_peer.py,
as specified in llmessage/CMakeLists.txt. test_llsdmessage_peer.py sets the
environment variable PORT before running INTEGRATION_TEST_llhttpclient. While
it's not yet clear under what circumstances INTEGRATION_TEST_llhttpclient
could find PORT not set (getenv() returning NULL), it's obvious that in that
case, the previous code might well crash. Make it at least fail with an
explanatory message rather than a mysterious large negative integer. In
theory, occurrences of that message could help us solve the underlying issue.

Rev b7fd7c95c571 allows a developer to debug a failure in hashmap_test 1. Once
the test fails, rerunning that test will replay the same failure to try to
permit debugging it. But that behavior is extremely undesirable under
TeamCity! In a TeamCity run, don't even check for saved data file.