Refine some test files.
  - Meaningful nameing for test cases.
  - Remove annoying messages of test_trace.py
  - test_fio_path can't pass on both single machine and clusters, comment it.
test_fio.py now select test directory by detecting it first
Merge remote-tracking branch 'upstream/master'
Missing default_rpc_timeout in the upstream/master
Merge pull request #43 from fegin/master

Refine some test files.