Auto merge of #17619 - clarcharr:master, r=SimonSapin

Update parse-hosts.

The `parse-hosts` crate was recently updated so that it doesn't use any unstable features.

---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because tests were already implemented.

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Author: bors-servo

Cargo.lock

@@ -28,7 +28,7 @@ mime_guess = "1.8.0"
 msg = {path = "../msg"}
 net_traits = {path = "../net_traits"}
 openssl = "0.9"
-parse-hosts = "0.3.0"
+parse-hosts = "0.4.0"
 profile_traits = {path = "../profile_traits"}
 serde = "1.0"
 serde_json = "1.0"

components/net/Cargo.toml

@@ -41,19 +41,10 @@ pub fn replace_host_table(table: HashMap<String, IpAddr>) {
 }
 
 pub fn parse_hostsfile(hostsfile_content: &str) -> HashMap<String, IpAddr> {
-    let mut host_table = HashMap::new();
-
-    for line in HostsFile::read_buffered(hostsfile_content.as_bytes()).lines() {
-        if let Ok(ref line) = line {
-            for host in line.hosts() {
-                if let Some(ip) = line.ip() {
-                    host_table.insert(host.to_owned(), ip);
-                }
-            }
-        }
-    }
-
-    host_table
+    HostsFile::read_buffered(hostsfile_content.as_bytes())
+        .pairs()
+        .filter_map(Result::ok)
+        .collect()
 }
 
 pub fn replace_host(host: &str) -> Cow<str> {