`cwd` was not set before when get commit SHA. The default `cwd` is the current build directory. However, the build directory might not be the subdirectory of source. The `git` command will fail when that happened.

test=develop

test=develop

1. Non utf-8 characters within comments of OPs may lead to protobuf fail to parse_from_string
2. comment out some ops which not supported on windows
3. cuda libs may not be correctly linked to target on windows

test=develop

* Added beam search API to fluid/contrib

* Change as review comments

* API.spec change

* Doc updated

Convert all values to string

Change patch version to str

Replace {} to + in cmake regex match

Change the PADDLE_VERSION in develop branch to latest

* use -rpath to fix libmklml_intel.so not found

* only remain $ORIGIN/../libs in rpath of core.so

* test

* test

* add rpath of libmkldnn.so.0

* check return value of os.system

* remove check return value of patchelf

* fix trainer import error on ce

* fix setup.py.in

In this way we can build and test using WITH_FLUID_ONLY flag being set
to ON.

- move paddle.v2.dataset,reader to paddle.dataset,reader
- remove unused code (which depends on v2) in paddle.dataset,reader