Set nolimit (infinity) as the error mode since this is Rust-specific

Author: j1ah0ng

src/sys/resource.rs

@@ -134,10 +134,9 @@ pub fn getrlimit(resource: Resource) -> Result<(Option<rlim_t>, Option<rlim_t>)>
 /// [`Resource`]: enum.Resource.html
 pub fn setrlimit(resource: Resource, soft_limit: Option<rlim_t>, hard_limit: Option<rlim_t>) -> Result<()> {
     let mut rlim: rlimit = unsafe { mem::uninitialized() };
-    // TODO: How do we handle the case where soft_limit isn't Some()?
     rlim.rlim_cur = soft_limit.unwrap_or(RLIM_INFINITY);
     rlim.rlim_max = hard_limit.unwrap_or(RLIM_INFINITY);
-
+    
     let res = unsafe { libc::setrlimit(resource as c_int, &rlim as *const _) };
     Errno::result(res).map(|_| ())
 }