Add -fno-exceptions flag to ROCKSDB_LITE.

Summary: Add -fno-exceptions flag to ROCKSDB_LITE.

Test Plan: make OPT=-DROCKSDB_LITE shared_lib -j32

Reviewers: sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D29901