Upgrade rust/crates/nix to 0.22.0

Test: make
Change-Id: I3997c62033aaf9734073fd1aa6e6da0d9c522034
diff --git a/test/common/mod.rs b/test/common/mod.rs
index 8a79d6a..cdc3258 100644
--- a/test/common/mod.rs
+++ b/test/common/mod.rs
@@ -31,6 +31,20 @@
     }
 }
 
+/// Skip the test if we don't have the ability to mount file systems.
+#[cfg(target_os = "freebsd")]
+#[macro_export] macro_rules! require_mount {
+    ($name:expr) => {
+        use ::sysctl::CtlValue;
+        use nix::unistd::Uid;
+
+        if !Uid::current().is_root() && CtlValue::Int(0) == ::sysctl::value("vfs.usermount").unwrap()
+        {
+            skip!("{} requires the ability to mount file systems. Skipping test.", $name);
+        }
+    }
+}
+
 #[cfg(any(target_os = "linux", target_os= "android"))]
 #[macro_export] macro_rules! skip_if_cirrus {
     ($reason:expr) => {