Update external / builtin openssl

We're building against an outdated openssl.

1) coordinate with LCG to provide (at least) the tar file of openssl 1.0.2m, see https://www.cvedetails.com/version-list/217/383/1/Openssl-Openssl.html?sha=7b1ad6e227215bdd832db256d5c0ec59c9887c99&order=1&trc=286

2) update all active ROOT branches to reference that version in cmake/modules/SearchInstalledSoftware.cmake for builtin_openssl