windows: uv_spawn shouldn't reject reparse points

This fixes an issue where uv_spawn would not try to run a reparse point,
and continue to scan the PATH instead. Effectively, it was impossible to
spawn a symlinked binary. This commit fixes that.

Also see #748

This is a backport of 495d1a0 to the v0.8 branch.

src/win/process.c

@@ -166,7 +166,7 @@ static wchar_t* search_path_join_test(const wchar_t* dir,
   attrs = GetFileAttributesW(result);
 
   if (attrs != INVALID_FILE_ATTRIBUTES &&
-     !(attrs & (FILE_ATTRIBUTE_DIRECTORY | FILE_ATTRIBUTE_REPARSE_POINT))) {
+      !(attrs & FILE_ATTRIBUTE_DIRECTORY)) {
     return result;
   }