Improve statistics by auto gen enum Ticker & enum Histogram
librocksdb-sys/Makefile: Add gen_statistics and gen_statistics.bash, make -C librocksdb-sys gen_statistics will generate 2 files: src/statistics_enum_ticker.rs src/statistics_enum_histogram.rs
In statistics.rs, we include! these 2 files and remove old hand writing enum Tickers & enum Histograms.
File gen_statistics.bash is used for generating these 2 files which is called in Makefile.
librocksdb-sys/Makefile: Add gen_statistics and gen_statistics.bash, make -C librocksdb-sys gen_statistics will generate 2 files: src/statistics_enum_ticker.rs src/statistics_enum_histogram.rs
In statistics.rs, we include! these 2 files and remove old hand writing enum Tickers & enum Histograms.
File gen_statistics.bash is used for generating these 2 files which is called in Makefile.