Fix the scope of the lock in pem.Files.Write().

pkg/pem/pem.go

@@ -345,6 +345,9 @@ func (pemfiles *Files) Write(
 //
 // Delete is protected by a write lock.
 func (pemfiles *Files) Delete(namespace, name string) (bool, error) {
+	pemfiles.mtx.Lock()
+	defer pemfiles.mtx.Unlock()
+
 	key := namespace + "/" + name
 	pem, exists := pemfiles.Files[key]
 	if !exists {
@@ -352,9 +355,6 @@ func (pemfiles *Files) Delete(namespace, name string) (bool, error) {
 	}
 	path := pemfiles.Path(pem)
 
-	pemfiles.mtx.Lock()
-	defer pemfiles.mtx.Unlock()
-
 	if err := os.Remove(path); err != nil {
 		return !os.IsNotExist(err), err
 	}