all: make certificates mandatory

state/open.go

 package state
 
 import (
         "errors"
         "fmt"
         "strings"
         "time"
 
         "labix.org/v2/mgo"
         "labix.org/v2/mgo/txn"
@@ skipping 36 matching lines @@
         log.Printf("state: opening state; mongo addresses: %q", info.Addrs)
         if len(info.Addrs) == 0 {
                 return nil, errors.New("no mongo addresses")
         }
         var (
                 session *mgo.Session
                 fwd     *sshForwarder
                 err     error
         )
         if len(info.CACert) == 0 {
-                return nil, errors.New("no CA certificate")
+                return nil, errors.New("missing CA certificate")
         }
         if info.UseSSH {
                 // TODO implement authorization on SSL connection; drop sshDial.
                 if len(info.Addrs) > 1 {
                         return nil, errors.New("ssh connect does not support multiple addresses")
                 }
                 fwd, session, err = sshDial(info.Addrs[0], "")
         } else {
                 session, err = mgo.DialWithTimeout(strings.Join(info.Addrs, ","), 10*time.Minute)
         }
@@ skipping 127 matching lines @@
         err1 := st.watcher.Stop()
         err2 := st.pwatcher.Stop()
         st.db.Session.Close()
         for _, err := range []error{err1, err2} {
                 if err != nil {
                         return err
                 }
         }
         return nil
 }