Remove non-existing functions. Closes #680

Summary: See https://github.com/facebook/rocksdb/issues/680

Test Plan: compiles

Reviewers: sdong, yhchiang, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47721

include/rocksdb/c.h

@@ -581,8 +581,6 @@ rocksdb_options_set_rate_limit_delay_max_milliseconds(rocksdb_options_t*,
                                                       unsigned int);
 extern ROCKSDB_LIBRARY_API void rocksdb_options_set_max_manifest_file_size(
     rocksdb_options_t*, size_t);
-extern ROCKSDB_LIBRARY_API void rocksdb_options_set_no_block_cache(
-    rocksdb_options_t*, unsigned char);
 extern ROCKSDB_LIBRARY_API void rocksdb_options_set_table_cache_numshardbits(
     rocksdb_options_t*, int);
 extern ROCKSDB_LIBRARY_API void
@@ -617,8 +615,6 @@ extern ROCKSDB_LIBRARY_API void rocksdb_options_set_skip_log_error_on_recovery(
     rocksdb_options_t*, unsigned char);
 extern ROCKSDB_LIBRARY_API void rocksdb_options_set_stats_dump_period_sec(
     rocksdb_options_t*, unsigned int);
-extern ROCKSDB_LIBRARY_API void rocksdb_options_set_block_size_deviation(
-    rocksdb_options_t*, int);
 extern ROCKSDB_LIBRARY_API void rocksdb_options_set_advise_random_on_open(
     rocksdb_options_t*, unsigned char);
 extern ROCKSDB_LIBRARY_API void