patch hcsshim to work with go1.9
patch hcsshim to work with go1.9

In go1.9, fi.IsDir() returns false if the directory is also a symlink.

See: https://github.com/golang/go/commit/1989921aef60c83e6f9127a8448fb5ede10e9acc

This breaks copyFileWithMetadata as it will not pre-create the
destination dir, causing the SetFileBasicInfo call to fail

This fixes the problem by checking syscall.FILE_ATTRIBUTE_DIRECTORY
directly.

Signed-off-by: Sam Smith <03a07629efb0a02c7bbe7cc340a4243da1ab861a@gmail.com>

Microsoft/hcsshim,madhanrm/hcsshim