.circle/config.yml: Add ROCKSDB_LIB_DIR and SNAPPY_LIB_DIR env vars
.circle/config.yml: Add ROCKSDB_LIB_DIR and SNAPPY_LIB_DIR env vars

So that build can use precompiled libraries

alekseysidorov/exonum,alekseysidorov/exonum,exonum/exonum,alekseysidorov/exonum,exonum/exonum,exonum/exonum,alekseysidorov/exonum,exonum/exonum