Fix exception raising in FakeConn

Timeout isn't an Exception, so Timeouts in tests weren't getting
raised. Instead, you'd sometimes have an HTTPResponse's .status be a
Timeout object, not an integer, which greatly confuses code that
expects an integer.

Also reorder the test that exposed the failure in the gate so it blows
up most times instead of sometimes do demonstrate the failure with out
this fix to FakeConn.

Change-Id: I76367a0575f84cad6b2f03e814f3f16bf96bc7d1
Merge "Fix exception raising in FakeConn"