Unify socket closers. Don't put them all in one try-catch or some might remain.

lib/units/provider/index.js

@@ -394,13 +394,16 @@ module.exports = function(options) {
   })()
 
   lifecycle.observe(function() {
-    clearTimeout(totalsTimer)
+    [push, sub].forEach(function(sock) {
+      try {
+        sock.close()
+      }
+      catch (err) {
+        // No-op
+      }
+    })
 
-    try {
-      push.close()
-      sub.close()
-    }
-    catch (err) {}
+    clearTimeout(totalsTimer)
 
     return Promise.all(Object.keys(workers).map(function(serial) {
       return workers[serial].cancel()