rpc: tests are unreliable

[Dave Cheney]

Depending on the machine, time of day, and color of the sky, rpc tests succeed or pass

The failure modes differ, here is a sample.

----------------------------------------------------------------------
FAIL: rpc_test.go:319: suite.TestServerWaitsForOutstandingCalls

[LOG] 70.76707 INFO: rpc: discarding obtainer method reflect.Method{Name:"callError", PkgPath:"launchpad.net/juju-core/rpc_test", Type:(*reflect.commonType)(0x6d21d0), Func:reflect.Value{typ:(*reflect.commonType)(0x6d21d0), val:(unsafe.Pointer)(0x4259ba), flag:0x131}, Index:3}
[LOG] 70.76718 INFO: rpc: discarding obtainer method reflect.Method{Name:"called", PkgPath:"launchpad.net/juju-core/rpc_test", Type:(*reflect.commonType)(0x6b3e90), Func:reflect.Value{typ:(*reflect.commonType)(0x6b3e90), val:(unsafe.Pointer)(0x425d00), flag:0x131}, Index:4}
[LOG] 70.76729 INFO: rpc: discarding obtainer method reflect.Method{Name:"testCall", PkgPath:"launchpad.net/juju-core/rpc_test", Type:(*reflect.commonType)(0x6ed378), Func:reflect.Value{typ:(*reflect.commonType)(0x6ed378), val:(unsafe.Pointer)(0x426c18), flag:0x131}, Index:5}
[LOG] 70.76786 INFO: send client request header: &rpc.Request{RequestId:0x1, Type:"DelayedMethods", Id:"1", Request:"Delay"}
[LOG] 70.76804 INFO: got response header &rpc.Response{RequestId:0x0, Error:"", ErrorCode:""}
[LOG] 70.76809 ERROR: rpc: client protocol error: unexpected EOF
rpc_test.go:338:
    chanRead(c, ready, "DelayedMethods.Delay ready")
rpc_test.go:357:
    c.Fatalf("timeout on channel read %s", what)
... Error: timeout on channel read DelayedMethods.Delay ready

OOPS: 8 passed, 1 FAILED

[Roger Peppe (rogpeppe)]

fixed by lp:~rogpeppe/juju-core/248-fix-rpc-test-race