Summary:
- This removes `folly/**/*.h` in `source_files` which causes all headers to be included. Instead we include only the headers needed to build. In my case this caused a conflict with folly's "Zlib.h" getting included instead of the system "zlib.h" (apparently paths are not case sensitive).
- Remove duplicates in `public_header_files`, we can just keep `"folly/**/*.h"` to make all headers public.
- Remove `preserve_paths`, this is not be needed anymore.
## Changelog
Cleanup Flipper-Folly.podspec included headers
Pull Request resolved: https://github.com/facebook/flipper/pull/518
Test Plan: Tested in an app that everything build using the modified podspec.
Reviewed By: jknoxville
Differential Revision: D16918216
Pulled By: priteshrnandgaonkar
fbshipit-source-id: 81cc9891c67bcb019580eb21d1b8e6d7318a4e03