Print compression_size_percent as a signed int

Summary:
compression_size_percent is an int but was printed as
an unsigned int. So the default of -1 is displayed as a big number.

Test Plan: make check

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D23679
Add rate limiter
Merge branch 'master' of https://github.com/facebook/rocksdb
Merge pull request #302 from ankgup87/master

[Java] Add rate limiter