Link the mysqlecollection to OpenSSL on FreeBSD

...in an attempt to fix the build on the CI. Raises the required
cmake version to 3.4 for the imported target usage. Borrowed from
https://svnweb.freebsd.org/ports/head/audio/amarok-kde4/files/
patch-src_core-impl_collections-db-sql-mysqlcollection-CMakeLists.txt?revision=453473&view=markup