be async: avoid double close()

In case when between this two close (close(F), close(F)) some open()
will be executed, than we will close newly opened fd.

Reported-by: xujiezhige@163.com
Merge pull request #189 from azat/be_async-avoid-doule-close

be async: avoid double close()
Fix cmake error when the Module path has more than one entry.

CMAKE_MODULE_PATH is usually a list instead of single entry. Especially
for projects contain sub cmake projects. My patch replace the
CMAKE_MODULE_PATH with fixed path, to locate the `.in` file.