(trapped) error reading bcrypt version

[Vincent Maillol]

Hello, is it possible to apply this patch in order fix  error reading bcrypt version ?

```
--- <old> passlib/handlers/bcrypt.py
+++ passlib/handlers/bcrypt.py
@@ -609,7 +609,10 @@
         except ImportError: # pragma: no cover
             return False
         try:
-            version = _bcrypt.__about__.__version__
+            try:
+                version = _bcrypt.__about__.__version__
+            except AttributeError:
+                version = _bcrypt.__version__
         except:
             log.warning("(trapped) error reading bcrypt version", exc_info=True)
             version = '<unknown>'
```

Thanks