librocksdb_sys: use tikv-jemalloc-sys (#520) (#521)

Jemallocator has not been active for several months. We published our
own fork, which upgraded jemalloc to 5.2.1.
Signed-off-by: Jay Lee <BusyJayLee@gmail.com>

librocksdb_sys/Cargo.toml

@@ -14,7 +14,7 @@ tempdir = "0.3"
 
 [features]
 default = []
-jemalloc = ["jemalloc-sys"]
+jemalloc = ["tikv-jemalloc-sys"]
 # portable doesn't require static link, though it's meaningless
 # when not using with static-link right now in this crate.
 portable = ["libtitan_sys/portable"]
@@ -24,8 +24,8 @@ sse = ["libtitan_sys/sse"]
 cc = "1.0.3"
 cmake = "0.1"
 
-[dependencies.jemalloc-sys]
-version = "0.1.8"
+[dependencies.tikv-jemalloc-sys]
+version = "0.4.0"
 optional = true
 features = ["unprefixed_malloc_on_supported_platforms"]