Revert adding openssl dependency
Revert adding openssl dependency

Summary: Remove the openssl dependency because it breaks other OSS builds (see D37695718). Add a comment explaining how we get this dependency in a system-specific manner.

Reviewed By: avalonalex

Differential Revision: D38056973

fbshipit-source-id: 70f0c5fa2a65cfa721a6bfa3223316997a79cf2d

facebook/wangle,facebook/wangle,facebook/wangle