Fix compression dictionary clang errors

Summary: There were a few narrowing conversions that clang didn't like.

Test Plan:
  $ make clean && USE_CLANG=1 DISABLE_JEMALLOC=1 TEST_TMPDIR=/dev/shm/rocksdb OPT=-g make -j32 check

Reviewers: IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57351

db/c.cc

@@ -1574,7 +1574,7 @@ void rocksdb_options_set_compression_per_level(rocksdb_options_t* opt,
 
 void rocksdb_options_set_compression_options(rocksdb_options_t* opt, int w_bits,
                                              int level, int strategy,
-                                             size_t max_dict_bytes) {
+                                             int max_dict_bytes) {
   opt->rep.compression_opts.window_bits = w_bits;
   opt->rep.compression_opts.level = level;
   opt->rep.compression_opts.strategy = strategy;

include/rocksdb/c.h

@@ -538,7 +538,7 @@ extern ROCKSDB_LIBRARY_API void rocksdb_options_set_max_open_files(
 extern ROCKSDB_LIBRARY_API void rocksdb_options_set_max_total_wal_size(
     rocksdb_options_t* opt, uint64_t n);
 extern ROCKSDB_LIBRARY_API void rocksdb_options_set_compression_options(
-    rocksdb_options_t*, int, int, int, size_t);
+    rocksdb_options_t*, int, int, int, int);
 extern ROCKSDB_LIBRARY_API void rocksdb_options_set_prefix_extractor(
     rocksdb_options_t*, rocksdb_slicetransform_t*);
 extern ROCKSDB_LIBRARY_API void rocksdb_options_set_num_levels(

include/rocksdb/options.h

@@ -149,7 +149,7 @@ struct CompressionOptions {
 
   CompressionOptions()
       : window_bits(-14), level(-1), strategy(0), max_dict_bytes(0) {}
-  CompressionOptions(int wbits, int _lev, int _strategy, size_t _max_dict_bytes)
+  CompressionOptions(int wbits, int _lev, int _strategy, int _max_dict_bytes)
       : window_bits(wbits),
         level(_lev),
         strategy(_strategy),