Use rand-core 0.1.0-pre.0 release

Author: dhardy

Cargo.toml

@@ -36,7 +36,7 @@ libc = { version = "0.2", optional = true }
 winapi = { version = "0.3", features = ["minwindef", "ntsecapi", "profileapi", "winnt"], optional = true }
 
 [dependencies]
-rand_core = { path = 'rand_core', default-features = false }
+rand_core = { version = '0.1.0-pre.0', default-features = false }
 
 log = { version = "0.4", optional = true }
 serde = {version="1", optional=true}